On the high plains of Kansas in a tiny town worn down by drought, I stop at a roadside diner. When I ask for water, the waitress pours me a glass of ice water, presenting it with obvious pride. “We have our own well,” she says. “And the wind turbine on the roof keeps the freezer going even when the grid is out.”

“That’s wonderful,” I say, and I mean it. The well water is sweet and clean and cold. At my last stop, some thirty miles back, I had filled my water bottles with lukewarm water that tasted like dust.

I order coffee and an almost-burger—with a patty that’s half black beans and half beef. Given the high cost of beef, the all-beef burger has become a luxury, even in America’s heartland.

When the waitress brings my order, she lingers, leaning against the counter. She’s in her twenties, I’d guess. Clearly, she’s curious about me. An old lady on a bicycle rides up to your cafe in the middle of nowhere. Who wouldn’t be curious?

I’m guessing that most of the people who stop at this diner know the waitress’s name, but she’s wearing a name tag. “Melinda,” I say. “That’s a lovely name. I’m Sandy.”

Melinda asks the usual questions and I give my usual answers. I’m traveling by bicycle because I want to see the country. I’m writing a book. (No one ever asks what the book is about. So few are interested in books these days.) With the solar-powered electric booster motor, my bike’s maximum speed is thirty miles per hour. I average about fifty miles a day on the flat. I’m heading for San Francisco.

“Where did you start?” she asks.

“New York,” I say. That’s where I started riding the bike. More accurately, my journey started at the research station in Greenland where I worked for many years. Or you could say it started in Oslo, where I lived with my husband after we left the station. But I think it’s best not to mention all that. I’ve read too much about Americans who blame scientists for not fixing the climate, about conspiracy theorists who claim that scientific efforts made climate change worse. Simplest to say I started in New York and avoid all that.

Melinda frowns. She is worried for me. When you reach a certain age, many kindhearted people worry about you.

“It’s a long way to San Francisco,” she says. “Why are you going there?”

“It’s my home,” I say. “Or it was many years ago.”

Back in Norway, my sister-in-law Hannah did her best to talk me out of this trip. “San Francisco won’t be the place you remember,” she said. “I know you miss Erik. We all do. But your friends and family are here. This is where you belong.”

I love Norway. But after my husband’s death, it became more difficult to feel that I belonged there. When Erik and I married, I gained a family and friends. But even after decades in Oslo, I was still the American. A much loved American, but always set apart.

“I’m homesick,” I told Hannah, and she frowned.

“But this is your home,” she insisted.

Melinda looks out the window at my bicycle. “I guess you’re not in a hurry to get home,” she says.

I shrug. “Sometimes, travel is about the journey, not the destination.”

A glib response. This trip is all about the destination. But Melinda is right: I’m not in a hurry to get there.

I change the subject, asking her what it’s like to live in such a small town, so far from the cities. I learn that she went to the city for college—that would be the big city of Salina, with a population of about forty thousand. But she came back home to help her family. “The city was okay, but it’s great to be home.” She has a bachelor’s degree in mechanical engineering and she works part-time at the nearby wind farm.

She asks about where I’ve been and what I’ve seen. That’s the opening I’ve been waiting for. Whenever I’m online, I check the Ghost Network for information about Ghosts nearby, but my best intel always comes from chatting with locals. I’ll mention the last Ghost I visited, then use that as an excuse to ask leading questions.

“I saw a Ghost back in Columbia, Missouri. People called it a Ghost, but it wasn’t a ghost like in a haunted house. It wasn’t frightening. It just made me feel different, made me think about things differently . . .” I shook my head, letting the words trail off. She is watching me in a way I’ve come to recognize. She knows what I’m talking about.

“I’m looking for Ghosts as I travel,” I say. “It sounds silly, I’m sure.”

“It doesn’t.” She hesitates. People who appreciate Ghosts protect them by keeping their locations secret, to be shared only with others who appreciate them.

I smile at her. “Not everyone understands.”

She nods slowly, then says, “There’s a farm not far from here. Well, it used to be a farm. Now it’s just an abandoned farmhouse owned by the company that bought up all the farms around here. There’s a Ghost there. I go visit him sometimes.” She gives me directions to the farmhouse. “Could you clean off the solar panel when you’re there? I always do that—to keep him going, you know. Say hello for me.”

• • • •

The farmhouse is several miles off the main road, but Melinda’s directions are excellent and I find it easily. Half its roof is gone, torn away by a long ago storm. The roof rafters are held aloft by walls that are leaning, not quite ready to fall, but almost. The front steps of the farmhouse are intact, but they lead to a sagging door frame that lacks a door.

A few fence posts mark the boundaries of what was once a garden, now overtaken by native grasses. It’s early October, the end of a long rainless summer, and the dirt is bone dry. A cedar tree, planted long ago by the look of it, casts a shadow on the front steps.

I walk around the dilapidated structure. High on one of the leaning walls, there’s a solar panel, positioned to catch the afternoon light. A long-handled mop hangs from a hook in the wall. I use the mop to wipe the solar panel clean, then I sit on the front porch, grateful for the shade of the tree.

Some Ghosts are triggered by motion; some, by sound. My movement has had no effect. Remembering what Melinda told me, I say, “Hello?”

Meeting a Ghost is like stepping into someone else’s dream and making it your own.

I see a young man standing in the yard. He is tall, raw-boned, dressed in worn blue jeans, work boots, and a faded t-shirt emblazoned with the name of a rock band that has long since disbanded.

No, wait—I’m not watching a young man. I am that young man, standing in the yard and smelling rain on the breeze that cools my face. I feel a warm affection for this place, for this house, for the old cedar tree that grows here. This house belongs to someone I care about—to my grandmother, who has moved to town. I am taking care of the house for her.

I hear thunder in the distance and I know that rain is coming. The wind moves the branches of the cedar tree.

No, wait. I’m not the man. I am the cedar tree and my roots reach into the ground, growing deep and wide in a quest for water. The wind increases and the storm is upon me. The wind tears at my branches, but it can’t tear me away from this place. I am rooted here. This is my home. I have been growing here for a hundred years and I will keep on growing for a hundred more. I belong here.

The wind blows and the storm comes. Hail hammers on my branches and on the ground around me. Cold melt water trickles down through the soil to reach my roots, and I am grateful.

I come back to myself slowly. The air is still and dry, but I remember the wind and the trickling melt water with its welcome moisture. A bird calls in the cedar tree. I stand and place my hand on the trunk of the tree, savoring my affection for this place, filled with hope for its future. For a time, I’m not quite myself, and that’s a welcome respite.

I breathe deeply, relaxing in the Ghost’s sense of belonging. It’s difficult to sort out the feelings—which are mine and which belong to the Ghost?

• • • •

Back in the late 2030s, outlaw artists with mad technical skills created the entities that have come to be known as Ghosts. The media gave the artists a name, the Mesmerists, and implied that the Mesmerists were an official Art Movement.

But they weren’t. They were artistically minded science geeks with technical skills—game developers, marketing engineers, digital artists, and the like. They worked outside the law, using techniques that had been banned in advertising and video games. Like graffiti artists, they placed their work where people could be surprised by it—never in a museum or gallery. The people who made the Ghosts were scattered all over the country, and so are the Ghosts.

Though I have visited many Ghosts, I still find it difficult to describe what a Ghost is. I could say that a Ghost is a mental illusion created by carefully calibrated electromagnetic fields interacting with your brain. I could tell you that the first proto-Ghost was created by a neuroscientist turned game engineer who realized that low-frequency electromagnetic fields generated by a gaming headset could change players’ emotional experience of a game—terrifying players or bolstering their confidence, making them want to play more or making them stop playing altogether.

When you visit a Ghost, magnetic fields shape your emotional response. A holographic projection gives you a focus for what you feel. Then your brain does the rest, filling in the gaps.

A Ghost is a story that you tell yourself to make sense of the world.

But a Ghost is more than that. A Ghost is a part of a life, left behind. A Ghost is a flower pressed in a family Bible, retaining its color but none of its scent.

• • • •

The feelings supplied by the Ghost fade slowly. Gradually, I become myself again—a woman sitting on a porch in the shade of a cedar tree.

I watch the sky. Puffy clouds float past, slowly shifting and changing as they move. As a kid, I might have identified them as “cloud that looks like a fish” and “cloud that looks like a heart.” As someone who has been studying clouds for decades, I identify them as Cumulus humilis—literally, the humble clump. Their edges are tattered and wispy, a sign that the water droplets that form them are evaporating. These are fair weather clouds—they will float away without releasing the water they hold.

Clouds are tricky beasts. In the winter, low clouds can keep an area warm by holding the heat close to the earth. In the summer, low clouds can keep an area cool by reflecting the sun and shading the earth.

Thirty years ago, I set sail on the Maker of Clouds, a research ship bound for the Arctic Circle. There I worked with a research team that studied Arctic clouds with one goal: increasing the sunlight that those clouds reflected back into space. We worked to make clouds that would cool the Arctic and reverse the melting of the polar cap.

In Kansas, as Cumulus humilis float northward, I write about the Ghost at the abandoned farmhouse. The book I’m writing is a catalog of Ghosts, with each entry describing a single Ghost. I’m writing this book for myself—I’ll never show it to anyone. I too am protective of the Ghosts for that.

For each Ghost I visit, I write a haiku. I learned to write haiku from Hikari, a Japanese researcher aboard the Maker of Clouds. As a discipline, Hikari wrote a haiku each day. I’m not a poet, but I adopted Hikari’s haiku practice back then—and I still find it soothing.

• • • •

Excerpt from A Catalog of 21st Century Ghosts

Location: Abandoned Farmhouse, Kansas, USA

Title: The Cedar Tree

Hail strikes like a fist.
Shreds leaves, breaks branches. But then—
A drink of cool water.

• • • •

When I leave the farmhouse, I head west—pedaling my bike past the wind farm where Melinda works. In the late afternoon, I set up camp just a few miles past the last wind turbine. All night long, I hear the rotors of the wind turbines turning, a soft sound like ocean waves in the distance.

To avoid going over the Rocky Mountains, I head south into New Mexico, across Arizona, and into Nevada. I visit a few Ghosts along the way: one in a Santa Fe cactus garden, another at an abandoned tourist stop in Arizona.

Each day, I wake before the sun is up to start riding in the cool of the morning, glad to be making this trip in October, when temperatures are relatively mild. Here in the desert, the bones of the earth are laid bare. These open spaces change my perception of time. I can see history in the layers of rock—lava rock from volcanoes that erupted almost two billion years ago, sedimentary rock that contains fossil corals from the inland sea that covered this land just a couple of hundred million years back.

In northern Nevada, I make my way toward Pyramid Lake, one of the last remnants of the inland sea where corals once grew. I stop short of the lake at a roadside business with a hand-painted sign that says “Tate’s Place” and lists what the business has to offer: burgers, sodas, gas, bait, buffalo jerky, and camping spots on the Truckee River. There’s one pickup truck in the parking lot, one woman at the counter inside. She has dark eyes, broad cheekbones, and short dark hair.

I sit at the counter and order a burger and a 7Up. The dark-haired woman is the cook and waitress as well as the checkout clerk. She serves the burger and soda, then asks me, “Where are you coming from?”

“I started in New York.”

“Long ride.”

I nod and sip my drink, knowing other questions are coming and also knowing it is best to wait for them.

“What brings you here?”

“I’m on my way to San Francisco.”

“You’re taking a roundabout route to get there.”

I nod. “I’m looking for something.” Out here in the west, people are friendlier to outsiders and Ghosts. From the tribal notices on the store’s bulletin board, the baskets on sale, and from the woman’s broad cheekbones, I guess that she’s a member of the local Paiute tribe. “I’ve heard that there’s a Ghost not far from here.”

She remains silent, waiting for me to continue.

“I am visiting Ghosts as I travel,” I say.

“How many have you seen?”

“Thirty-five. It would have been thirty-seven, but two had been vandalized. Beyond repair. Not everyone approves of lingering dreams.”

She nods, looking thoughtful. “Why are you visiting Ghosts?”

“I’m looking for something.”

“What are you looking for?”

I hesitate, then say, “Any name I gave it would sound stupid or pretentious.”

She chuckles then. Her face, weathered from the sun, changes when she laughs. “I’ll give you points for awareness. Lots of people come here talking about vision quests and spiritual journeys. They want to sound like they’re humble and they’re doing a sacred thing. But they’re full of themselves. They sound pretentious as hell.”

I don’t say anything. Riding through the desert has made me patient.

“Why are you going to San Francisco? What’s there?”

I hesitate, then answer. “The last Ghost I plan to visit.”

“And what were you doing before you started riding your bike across the country?” This woman has a lot of questions, but now that I have started answering them, I see no reason to stop. It feels good to talk. I tell her about studying clouds, about working in Greenland, about living in Norway. I tell her about my husband’s death from a heart attack and the need I feel to go home. I even tell her that I write a haiku about each Ghost.

She listens calmly, then asks a question that has nothing to do with any of that. “And if you don’t find what you’re looking for in San Francisco? What then?”

“I don’t know.”

She nods again, this time as if she has come to a conclusion. “You can camp behind the store. The water from the pump is good for drinking. Tomorrow, I’ll take you to the Ghost. We’ll leave just before sunrise.”

“Thank you,” I say. “By the way, my name’s Sandy. I’m guessing yours is Tate.”

• • • •

I wake an hour before sunrise. Venus is a brilliant point of light in the eastern sky. The morning is cool, but I know that will change. I wipe my face with a damp bandana, then reapply sunscreen. For breakfast, I have an energy bar and some of the beef jerky that I bought at Tate’s store.

When I hear a door creak open and slam shut, I meet Tate in the parking lot and we head out. She drives on a dirt road that leads to another dirt road that leads to another—and so on.

Eventually we reach a pile of limestone boulders on the edge of a dry lake bed. One of the boulders is etched with geometric designs. “Archeologists say these petroglyphs are the oldest in North America,” Tate tells me. “Ten thousand years old, they say. My people have been here for a long time.”

She gestures toward the shadow of the limestone boulders. “I’ll leave you here. I’ll be back in an hour or so.”

I sit in the shade and study the petroglyphs. A pattern of diagonal slashes reminds me of a cartoon fishbone. An undulating line makes me think of ripples on water. I turn and gaze at the dry lake bed. The cracked clay shimmers in the heat.

Then I hear a woman singing in a language I don’t understand. When I look toward the sound, I see a woman standing beside the petroglyphs, singing as she uses her hand to trace the undulating line on the boulder. Her dark hair is braided. She wears a simple dress. As I watch, her hand reaches the end of the line on the rock and she finishes her song.

No, wait: I’m not watching the woman; I am the woman. My hand rests on warm stone, on a line that was carved long ago. I take my hand from the stone, turn away from the petroglyph, and walk to the edge of the dry lake bed.

My people have lived in this place for thousands of years. The lake that filled this valley gave my people all that we needed to live: fish and waterfowl to eat, reeds to weave into boats and baskets and shelters. Then the white people came and took away the water.

I close my eyes and I think about water rippling in the sun. I open my hands and I open my mind. I am high in the mountains where the snow is deep. The springtime sun shines on the snow and I hear the sound of water trickling as the snow melts.

I am melting with the snow, running downhill to join a stream, a river. I am a rushing torrent, a flood that batters and breaks the dam that tries to block the water’s flow. I am cool mountain water spreading across the dry lake bed, seeping into the dry soil, saturating the soil and filling the valley.

Then I am the woman again, feeling a cool breeze on my face. I open my eyes.

Sunlight shimmers on water. I wade into the lake up to my knees, murmuring a prayer of gratitude that the water has returned. Tiny fish flee my approach, taking refuge in a patch of reeds. I see a splash in the water—a larger fish, jumping to catch an insect. I hear geese gabbling in the distance.

Slowly, I come back to myself—feeling powerful and content. The lake is dry, but I know that can change. This land has been through many changes.

• • • •

Later, back at Tate’s Place, Tate grills me a burger and makes one for herself.

“So,” she says. “Did you write a haiku?’

“Not yet. I’m working on it.”

She nods.

“So tell me,” I say, “why did the lake dry up?”

“Back in 1905, the US government built a dam on the Truckee River,” she says. “The dam diverted water that would have gone into the lake, sending that water down a canal so that white farmers could use it to irrigate their fields. The dam was part of something they called the Reclamation Act. I’d say the government was reclaiming something that wasn’t theirs to begin with. Without that river water, the lake dried up. But now the world is changing. The climate is changing.”

People never smile when they talk about climate change, but Tate is smiling.

“Each year, the snowpack in the Sierra Nevada increases,” she says. “One year—maybe next year, maybe the year after that—the snowmelt will overwhelm the dam that the government built to control the water. Then the lake will return.”

• • • •

Excerpt from A Catalog of 21st Century Ghosts

Location: Dry lake bed, Nevada

Title: Reclamation

Dry lake. Mountain snow.
Water finds a new path. Yes—
Everything changes.

• • • •

The shortest route from the dry lake bed to San Francisco leads over the Sierra Nevada, following the path of the California Trail, where oxen pulled covered wagons more than a hundred years ago. I don’t take that route. It would be a slow uphill climb.

I take a longer route with less elevation gain, riding my bike south on back roads that run along the eastern side of the mountains down to the Owens Valley. I head west when I reach the town of Mojave, crossing California’s central valley at Bakersfield and making my way to the California coast.

The rising seas have gnawed at the cliffs along the shore. Sometimes storms and rising waves wash away the coastal road. When that happens, people rebuild it. If you want to take the coastal road, you must be adaptable and patient.

I start out patient, but when I reach Santa Cruz, a coastal town just a few days’ ride south of San Francisco, I am overcome by a sense of urgency that’s been quietly growing for days. I head inland, pedaling up into the Santa Cruz mountains, pushing myself to go faster. Muscles aching, I camp for a night in a patch of redwood forest. Then I hurry on, following Skyline Boulevard along the ridge of the mountains until I reach Daly City and then San Francisco, at last.

I reach the city late in the afternoon. I know where to find the Ghost I have come to visit, but I need a boat to get there.

I find my way to a traveler’s hostel in the Potrero Hill neighborhood. I ask the clerk at the desk about renting a boat. She gives me a map and directs me to a dock at Sixteenth and Owens, where a woman named Lucia rents kayaks and gives tours.

When I lived in San Francisco, Sixteenth and Owens was several blocks away from the water, but times have changed. Lucia’s dock is at the edge of DrownTown, part of the city that is now submerged beneath the rising waters of San Francisco Bay. Standing at the intersection, I can see the pavement of Sixteenth Street continuing below the water. Lucia’s kayaks float beside a makeshift walkway built of wood that has been reclaimed from fallen buildings.

Lucia, I discover, is a very stubborn woman. She refuses to let me take one of her rental kayaks out on the bay alone. She insists on accompanying me.

In vain I tell her I am a competent ocean kayaker. “I used to live here,” I say. “I lived in Dogpatch, just a few blocks from here. I used to kayak on the bay every weekend.”

“Lots of things that used to be are different now,” she says. “Where do you want to go?”

“Mission Rock.”

“Ghost hunting,” she says in a matter-of-fact tone. “A lot of disaster tourists want to go there.”

“I don’t need a guide,” I say, uncomfortable at being lumped in with disaster tourists. “I know the way.” I look toward the bay, toward Mission Rock. I am trying to match memories from thirty years ago with a very altered present. “I left a long time ago, but I still remember the way.” I hope that claim is true.

When I turn to look at her, something in her expression has changed. She is frowning as she studies my face. For a moment, I think that she will relent and let me go alone. Then she shakes her head and gestures at the sun, now low in the sky. “It’ll be dark soon. Easy to get lost. I’ll show you the way.”

I have no choice. I give in. “When we get there, you must leave me be. No tourist spiel.”

Lucia gives me a look I can’t read. “As you wish.”

She equips me with a life jacket and paddle. In a battered yellow kayak, she leads the way down what used to be Sixteenth Street. I follow in an equally ancient blue boat. Around us are broken buildings, flooded streets. When we are making our way around the remains of a structure that once supported traffic signals, I catch sight of a sign for a coffee shop.

I recognize the place. I knew the barista—we chatted whenever I stopped there for coffee. On my last day in the city, I met friends there for breakfast. I know where we are.

When I lived in the city, this neighborhood was called Mission Bay, named for the shallow cove that had once been here. The cove was filled in during the late 1800s to create more land for the growing city. Now the ocean has risen and the Mission Bay neighborhood is a bay once again.

It is a wonder how a person can fool themselves—that person being me. I knew the city of San Francisco had been flooded by rising seas, battered by storms. But until this moment that was just a story I had heard. Even when I saw the flooded street, it didn’t seem quite real.

But now that I see my favorite coffee shop under water, it is real.

I feel disoriented, confused. I wonder if my old house is now under the waters of the bay. My favorite waterfront dive bar and burger joint—a remnant of old San Francisco—is certainly submerged. My past is gone. All gone.

But I have no time to process this. I have to paddle quickly to catch up with Lucia as she moves out into the open water and turns north. Ahead, I can see what was once the city’s financial district. Some of the tall buildings are leaning. Water from the Bay had soaked and softened the soil. Like the walls of the farmhouse in Kansas, the buildings are ready to fall.

Lucia stops paddling and I wonder why. Then I catch sight of asphalt just a foot or so below the water’s surface. “Mission Rock,” she says. “I’m guessing it looked different last time you were here.”

Around the patch of submerged asphalt are artifacts from the broken city. I can see a stone ornament of a smiling woman’s face salvaged from a building in the financial district, a length of curb that retains a splash of red paint marking a “no parking” zone. Atop a pile of shattered bricks lies the torso and arm of a broken statue. The outstretched arm points skyward, reaching above the water.

Lucia tosses her bow rope around the outstretched arm. She grabs my bow rope as I come alongside her. Then she waves her paddle as if to catch someone’s attention.

For a moment, nothing happens. Have the motion sensors that trigger the Ghost failed?

My kayak rises and falls on the waves, a rhythm as steady as breathing. Then I see the air above the patch of asphalt shimmering. Mist rises from the water—a few wisps, then a cloud of white that fills my field of vision. A figure appears in the fog—a woman standing on the patch of asphalt. Her long dress is the color of fog. Her hair hangs loose around her shoulders.

I can feel the touch of fog on my skin. I remember that feeling. I take a deep breath, inhaling cool air that smells of the sea. I remember being embraced by the fog, knowing that this is where I belong.

“This city is my home; it’s where I belong,” the woman says. The Ghost is speaking, but she is speaking in my voice. “But I can’t stay here and wait for the changes that are coming. That’s just not right. I need to do something.”

As I watch, the woman lifts her arms and opens her hands. Fog billows from her uplifted hands . . . no . . . from my uplifted hands. I am making clouds that rise to blanket the sky.

I feel a surge of confidence—her confidence has become my confidence. I am once again young and strong and sure that I know the way. I will set sail on the Maker of Clouds, the ship that will take me to Greenland. I am setting forth on an adventure to save the world. I know that anything is possible. I am certain that when I return, the city will be waiting for me. It is a wonderful feeling.

Then, suddenly, the woman is gone. I am sitting in a kayak that rocks gently in the waves. The Ghost’s sense of certainty lingers.

I remember feeling so sure that there was a way forward, a way to stop the world from changing. I remember choosing a dress that would subtly remind viewers of a Greek robe and undoing my braid so my hair would move in the ocean breeze. I didn’t have the technical skills to make a Ghost, but I had friends who did. My friends did the hard work so I could leave a message behind.

I was twenty-five years old and I was ready to take on the world. I had a PhD in climate dynamics with a focus on the role of clouds in climate change and I was prepared to put my knowledge to use. I thought I’d be gone for a year, or maybe two. But when I was in Greenland, returning became impossible. No need to catalog all the calamities that happened in the Crazy Years; enough to say I couldn’t return home. I stayed in Greenland and fell in love. Erik and I married, moved to Norway, and worked together to save the world. I became a different person.

A Ghost is a piece of yourself that you have lost and can never recapture.

“Such a stupid young fool,” I mutter. Am I talking to myself, to the Ghost, to Lucia? I’m not sure and I suppose it doesn’t matter. “I’m sure the disaster tourists have a good laugh when they listen to her.”

“Why do you say that?” Lucia says. There’s an edge in her voice.

“She thought she could fix a problem that was hundreds of years in the making.” I say, my voice tight with anger and despair. I wave a hand at Drowntown with its abandoned buildings. “And she failed. My city is broken. A small shabby broken town in a country that’s a shadow of what it was.” My voice is shaking.

“Wait,” Lucia says, but I can’t listen. I yank my bow rope free of her hand and I paddle away from the foolish young Ghost who once was me. I am crying and I need to get away from the Ghost of my past, from Lucia who is witness to my pain.

I try to head for the Sixteenth Street dock, but I lose my way among the derelict buildings. I finally stop paddling when I see a landmark I recognize. The platform at the top of a playground slide stands just above the water’s surface. I stop by the platform and grab hold. I’m floating above the children’s playground at Mission Bay Kids’ Park.

I hear the sound of Lucia’s paddle cutting through the water as she catches up with me.

“There are some things you need to understand,” she says. I hear anger in her voice and that anger surprises me.

I start to speak but Lucia interrupts.

“You see a broken city, but that’s not what I see,” she says. “Disaster tourists don’t laugh at the Ghost you called a fool. I’d venture to say they find her inspiring. I certainly do. Why else would I have put in the time to keep her running all these years?”

“I thought . . .” I begin, but she interrupts again.

“You thought that system cobbled together thirty years ago had lasted all these years? Not a chance. My friends and I rebuilt that system from scratch to keep Cassandra going.”

She pauses for breath, glaring at me.

“I didn’t know . . .” I started, but I can’t speak. My mind is whirling. I focus on breathing.

Lucia’s expression softens. “You see a city that’s broken,” she says quietly. “I see a city that is alive and growing, changing a little bit each day. Small changes, but each one makes a difference. We didn’t just sit around and wait. We acted.” She paused for breath, studying me. “Did you think no one would recognize you here, Cassandra?” she says softly.

“I go by Sandy now,” I manage, but then I can say no more.

She regards me with concern. “When was the last time you ate?” she asks, but she doesn’t wait for an answer. “You need to eat. It’s happy hour at the Mussel Bar. We’ll go there. Follow me.”

• • • •

By the time we reach the Mussel Bar, the ocean air had cooled my face and filled my lungs. We tie the kayaks to a dock beside a few dozen others.

I follow Lucia to a picnic table in the center of an old warehouse, now functioning as a restaurant. Lucia gets an enormous bowl of steamed mussels in a white wine broth and a basket of bread for dipping in the broth. She pours me a beer. For a few minutes, we eat mussels and drink beer, surrounded by the noise of other diners.

Some of Lucia’s friends join us. She doesn’t introduce us. People look at me curiously, but they are talking amongst themselves about many things: the growth of eelgrass in the bay, oyster farming, sand dunes on the westernmost edge of the city, silt and tides and mussels and where seabirds are nesting. It reminds me of conversations at the research station. Everyone comparing notes over dinner, informal information-sharing that integrates the work of the community.

Listening to them talk, I learn about the city and how it’s changing. Seabirds are nesting on the skyscrapers downtown. The buildings might as well be cliffs, as far as the birds are concerned. Eel grass is thriving wherever the tides bring in silt. The roots of the eel grass hold the silt in place, building up a layer of rich soil that can support other vegetation. Oysters and mussels, once abundant in the waters of the bay, have returned. With human help, the shellfish are forming living breakwaters that could protect the city from storms.

The young man across the table asks me to pass the bread and then says, “Where are you from?”

“I’ve been traveling,” I say.

He raises an eyebrow. “Yeah? Where were you before you started traveling?”

He’s trying to figure out what I’m doing here. Lucia is not speaking up, so I tell him. “My last permanent address was Oslo, Norway. Before that, a research station in Greenland.”

His other eyebrow shoots up. “Really.”

“Sandy sailed on the Maker of Clouds,” Lucia says.

The conversations around us fall silent and everyone’s eyes are suddenly on me. Lucia speaks to me directly then. “So tell me: what was it like on the Maker of Clouds?”

Her words have a ritualistic tone, like the murmuring of a priest in the confessional, like a therapist muttering “tell me more about that.” There is a pause—the kind of pause that is an invitation to speak.

Some of the Ghost’s confidence is with me still. I take a deep breath.

“We’d watch the sky,” I say. “We’d sniff the air, hoping to smell the conditions that make the right kind of cloud. When the sunlight is too intense, microscopic plants in the water make sulfur compounds that react with the air and those compounds seed the clouds. The chemistry is complex, but the smell is simple and sweet, and the result is clouds that reflect sunlight.

“We tended those clouds, just as farmers tend their crops. We adjusted conditions so that the clouds that formed would reflect more sunlight, starting a feedback cycle to cool the planet. We set up stations to continue the process when we weren’t there.”

I pause for a moment, remembering how wonderful that time had been.

“Nice talk.” A harsh voice interrupted my reverie. “I guess all that didn’t do much good.” A bearded man is staring at me and scowling. “DrownTown is evidence of that.”

“It was too little and too late,” I say softly. “All the clouds in the world could not stop the rising seas. We slowed the melting of the polar cap, but we couldn’t reverse it. Without our work, it would have been worse.” I shrug, feeling the Ghost’s confidence leaving me. “But there’s no point in talking about degrees of disaster. You save the world or you don’t. And we didn’t.”

Lucia speaks up then. “The stations are still working, aren’t they? You set a process in motion. It takes time. Small steps.” She frowns at the bearded man, then speaks to the group. “It’s not so different from building a breakwater or restoring a wetland. Our projects are a little faster, but much smaller. Many small changes over time.”

Her listeners nod. This is something they have heard before, something they believe. The bearded man shakes his head, and heads for the bar.

The young man across the table leans toward me. “You gotta come see what we’re doing with dune grasses out in the Sunset district,” he says. “Their roots hold the soil, protect against wind erosion. Small changes, but eventually they’ll make a difference.”

I say I’d be happy to see what they’re doing in the Sunset. Others speak up about their efforts. Before the last mussel is devoured, I have agreed to visit the sand dunes, the mussel breakwater, and half a dozen other projects.

• • • •

I haven’t finished a haiku for Cassandra’s Ghost. Not yet. Like so many things—like everything in the world—that’s a work in progress. I’m working on it.

A Ghost is a story that you tell yourself to make sense of the world, and I’m still not quite sure how this story ends. I sent a message to Hannah, telling her that I’ve reached San Francisco and I’ll be staying here a while.

People talk about restless ghosts. I’ve realized that unfinished business is what makes a ghost restless. The only way to lay a ghost to rest is to finish the business, tie up the loose ends. It may take years, but you start small and you just keep going.