It had been a long day of convention. All I wanted was a quiet drink in the hotel bar and quality time in my room with a romance novel. The utter cad from Planetary Industries was an unanticipated bubble in the fuel line, but I was an experienced enough convention-goer that I probably should have known there’d be somebody.

I’d been coming to the Gift Shop & Outpost Managers’ Convention on the Bagratun Station off Europa for three years, and it was always a welcome break from the daily grind of managing the Ford-Io Memorial Hospital complex’s gift shops. I loved to compare notes, pick up the latest fads from in-system, eat some treats that my own station didn’t produce.

Mr. Planetary Industries was not letting anybody have a quiet drink. “Feast your eyes, friends!” he bellowed.

He was not my friend. My eyes stayed right on my handheld.

“This new souvenir—nay, keepsake—will be irresistible to any and all visitors to your fine establishments. You will be unable to keep them on the shelves, should you be so old-fashioned and gravity-bound as to use shelves.”

At Ford Memorial—as in most gift shops, alas—the main reason I cannot keep things on shelves—and you’re damned right I’m gravity-bound, it is, as they say, not just a good idea but the law—is because people nick them. I kept reading.

“Madam, won’t you give it a try?”

He was standing too close. I could still pretend he didn’t mean me. I don’t answer to “Madam.” But then there was a silver cube between me and my book. I looked up at him with disdain.

He was an aggressively ordinary human-standard man. He was wearing a t-shirt that said, “Earth: Order our steaks online now!” Earth people were so damnably proud of their protein.

“It’s a cube,” I said flatly. “I’ll pass.”

“Ah-ah-ah,” he said, wagging a finger at me in the least endearing fashion possible. “Not merely a cube!” It sprang into relief: a scale model of Bagratun Station, perfect in every detail. They probably had ten of them on the shelves in the gift shop at the moment.

“Lovely,” I said dryly, signaling the staff that I wanted to settle my bill.

“You haven’t seen what it can do!”

“I run the largest hospital gift shop in the sector. Our bestsellers are warm socks, papercraft books that don’t gum up the hospital recycling, soft spherical animals you can clutch while recovering from surgery, and those little wooden float-trains—you know the trains?”

He nodded eagerly.

“The little wooden float-trains that go over children’s beds. And do not get in the way of their medical equipment. That is what we sell the most of. No one wants a keepsake souvenir from my gift shop. They do not want to remember it. I am not your market segment. Go bother the First Landing Monuments shop people, I’m sure they’re drinking in the bar down the corridor. They bond every year. You’re just their sort of thing. Okay? Great. And that’s mine,” and there was the server with my bill, settled with a blink, hurrah, I could vacate the premises.

He actually tried to step into my path. “It can make all sorts of things! Craft projects, little trains . . . I don’t know about soft things yet, I’ll have to work on those . . .”

“You do that,” I said. “I wish you a good shift.”

I went back to my room and collapsed into lavender-scented sheets. Peace, quiet, and a panel about less-perishable snack items in the morning: whew.

The snack panel was as good as I’d hoped: two new flavorings I was sure would be popular and one I was willing to try and find out. To the layperson this sounds trivial, but for a gift shop manager it’s the difference between happy customers and bored, annoyed ones—and in a hospital gift shop in particular, circumstances prime customers to be bored and annoyed. Being able to give them lemon/sumac-flavored snacks when they’ve only had barbecue or chili/lime? It won’t change the results of their mother’s surgery, but it can improve the time spent waiting. Which is my job.

It’s not a glamorous job, but I like it. I got into a good chat with the waystation manager from out Ceres way—nice person, quiet, passionate about soy proteins.

Then Mr. Planetary Industries inserted himself in the conversation. Sigh. He had put on a fresh Earth t-shirt that morning: “Earth: You Probably Have Cousins Here.” Technically hard to argue, but if he was a representative sample, I didn’t want to know them.

“Hi! What have you been doing?” he said.

The Ceresian raised an eyebrow in the universal expression for “do you know him?” I shook my head minutely. “Snack flavors,” I said. “Nothing Planetary Industries cares about. We’re off to beverages.” We had made no such plan, but the Ceresian nodded vigorously, picking up on the conference signals of “avoid avoid avoid.”

“Well, when you’re done with consumables, be sure to stop by the Planetary Industries booth in the vendors’ hall,” he said. “We aim to be your one-stop shop for all souvenir goods—no need to go from vendor to vendor when you can get it all with one easy contract!”

“Please excuse us,” I said, and stepped around him. The Ceresian hurried after me.

“One easy contract?” they blurted incredulously.

“Like that’s never gone wrong before,” I agreed.

But they say there’s one born every nanosecond, even out in these parts, and plenty of rubes flocked to the Planetary Industries table. All I could do was hope they weren’t signing contracts that made their gift shops wholly owned and operated franchises of Planetary Industries, selling one cube and one cube only. I didn’t relish the vision of that future.

The chrome trim on the dais railings was shabbier than I’d ever seen it. Bagratun Station was usually meticulous about maintenance. But the keynote speaker was witty and mercifully brief. I learned things about shelving in variable gravity that I hoped to never use. As I walked out I noticed maintenance taking away some limp, yellow potted plants. Maybe they were just short on staff.

I saw Mr. Planetary Industries showing an annoyed crowd that his cube could also be a pot containing the sprout of an orchum or an orchis or whatever you call those Earth plants. His t-shirt said, “Earth: Birthplace of Willa Cather.” I heard his voice floating over the crowd, “Using Earth and local parts . . .” I dodged around the corner before I could hear how Planetary Industries provided the freshest Earth souvenirs.

I hoped for herring on the next morning’s breakfast buffet; Bagratun’s ventilation was usually up for it in one sector. But before I could get there, I stumbled on two maintenance people spackling a hole in the bulkhead. “What happened here?” I said. “A brawl?”

One shrugged. “We don’t have anything on the footage, that’s what’s weird. It just . . . disintegrated.”

Nobody wants to hear that bits of the space station they’re on are disintegrating. “How’s hull integrity?”

The other looked panicky. The first one said, “Fine it’s fine.” No pauses. This was not reassuring.

“I work at a hospital,” I said. “I’m trained in evac. Do they need my help?”

“No,” said the second staffer, as the first one said, “maaaaybe.” Yeah. Breakfast to go and Station Enviro as fast as I could manage. I was still sticking a blueberry protein bar in my face when I came upon Mr. Planetary Industries. His t-shirt said, “I Hate To Wake Up Sober On Earth.” I privately wondered how often this was a problem for him. He was tapping one of his obnoxious little cubes and looking annoyed.

“We’ve all got problems,” I muttered.

But self-awareness is not a problem we are all cursed with; he took me at my word. “Really? Are there other problems with nanites this morning? I’ve been trying to do the fuzzy sock thing you mentioned, but this one is fizzling out.” He tapped it against his palm, and it became a limp fibrous mass, like a skein of yarn someone had forgotten to secure when the grav was turned off.

“Nanites?” I said slowly.

“Right, mine are a mess.” He looked like a puppy eager for a cookie. I was not inclined to provide him with even the dubious anise kind I’d declined at the snack panel.

“Where . . . where do your nanites get materials to change the cube into other things?”

“Oh, local ingredients, I told you that. It’s a mix of Earth and local, all the best for our customers!”

Earth and local. Which meant that the nanites were just . . . harvesting whatever they needed. Or more accurately, wanted. “How do you block it, though?”

“What do you mean?”

I enunciated like I was talking through a comm link. “How do you make it not harvest the molecules it finds the easiest to use? Turn itself off?”

“But that’s how it works.”

“It is eating holes. It is killing plants. This is a small station. There’s not an infinite amount of spare chlorophyll, for example. Stop taking it. Don’t take more.”

He looked at me like I had started speaking machine code. “How will it change if it can’t take more?”

I rubbed my temples. “Say you’ve asked it to make something with chlorophyll. And then the next thing you ask it to make doesn’t need any. What does it do with the rest?”

“Breaks down the chemical bonds and uses it for the carbon and nitrogen and so on, I suppose,” he said promptly. “Or just outgasses it to pick up later.”

“Out . . . gas . . . okay, that’s it, I am reporting you to Station Enviro.”

“I don’t understand,” he complained. “They’ve been immensely popular on Earth, Luna, and Mars. We’ve had no problems.”

I smote my forehead softly. “Those are planets, you utter nugget.” He still wasn’t getting how fast things could go haywire in a small closed system. “What is the simplest thing you can make it be and lock it in there? And all of them, do all of them.”

“I can’t do all of them at once.”

“The simplest thing. This is important,” I repeated.

His face cleared. “Probably the station models I first showed you.”

“Great, put that on broadcast for everything you’ve sold, and lock it down not to change.”

“Oh no, that won’t work,” he said. “It would probably cost us business. I’d lose my bonus.”

It might be easier to work with this idiot, but now that I knew what was wrong, I could get other people to make him fix it. And this? This was a convention. I snapped a photo of him and sent it to Enviro and made for the first panel of the day, which was Apparel Size Inventory And Your Shop’s Demographic. Mr. Planetary Industries followed me, looking muddled and curious. The panelists had just finished the main body of the panel, so I spotted my chance. My hand shot up.

. . . and I nearly got us all killed with a time-sucking newbie mistake that had nothing to do with the nanites and everything to do with the audience I was trying to reach. I forgot to rephrase my information about what was going on as a question, and audiences absolutely hate things that are more comments than questions. But when the comment is, “I’ve discovered who’s messing with Station Enviro, and it’s this guy,” they do get over it in time to act.

Mostly. I still got some glares in the bar that night. But Mr. Planetary Industries was apprehended by Station Security, and the programmers from the Turing Monument in Neptune’s Courage Arc managed to convince all the cubes to stay models of the station.

Every single one of them had a hole in the middle, which was even worse for business among the in-system convention attendees than the incident itself had been. Made them look cheap. Planet-dwellers, who can understand them.

I saw the guy escorted off-station. They had at least let him change into clean clothes before they marched him off. His latest shirt read, “Earth: It’s Not For Everyone.”

Wasn’t that the truth.