Josea Dream was the pearl captain at the heart of the bivalve ship Blue Spring, which had swum the black for a thousand years. It was a mystery to Josea—it was a mystery to anyone who’d ever thought about it—why the bivalves suffered their captains’ proddings to go one direction or another, to accelerate, to turn, to open the hatches drilled in their kilometer-thick aragonite shells.

Josea did not like mysteries. This did not mean that he wanted to solve this one—or to solve any other. His expression of dislike of mysteries was to ignore them, to not ask questions, to be as incurious as it is possible for a go-man to be.

Go-men can be very incurious. It is a trade secret of their guild that there are more dampeners than heighteners in the living clays packed over their transparent skulls.

On the day Josea Dream became the pearl captain of the Blue Spring, a delegation of Martian eremites accompanied him into the flesh, swinging censers, shouting shouts, chanting chants, and dancing dances. The bivalve, which dwarfed Deimos, yawned a third of the way open. This only happened when a new pearl captain was installed. It would close again once the eremites had removed the oblong conchiolin shape of Josea’s predecessor.

Josea was 241 years old, of middling age for a go-man, but very young for a pearl captain. He was only the fourth captain of the Blue Spring and was expected to last longer than any who had gone before him.

Twenty-one years into his captaincy, a droplet made up of nine liters of pure water fell from the fleshy ceiling of Josea’s bridge-cabin. He had been watching it form for several days. The sound of it splashing to the floor was muffled by absorbers built into the arrays that crowded the room, but Josea was thoroughly soaked. The water coalesced into worms with the consistency of mercury, which wriggled into Josea’s nostrils and ear canals.

Blue Spring wanted to talk.

You are still alive?

The question was freighted with all the age and weight of the ship. It pressed through the clays on Josea’s scalp.

“I live, Blue Spring.” Josea had been trained in imaging his voice, though he had only ever done so in simulations. This was to be expected, because the only creatures who could sense a go-man’s imagings were the bivalve ships, who did not condescend to participate in the training regimes.

For a long moment, there was no response, and Josea wondered if his training had been faulty. It did not occur to him to seek inside himself for a deficiency.

But then, You are different. You move.

“I am Josea Dream. We have never communicated directly before.”

You are the captain.

“Yes, Blue Spring. I am the fourth captain you have permitted since you reached your full growth.”

The response was in the form of a deep vibration through all the flesh of the ship. The arrays channeled some of their stored power into protecting themselves from damage, and more of it into protecting Josea.

The mercury-water worms flowed out of his ears and nose, returning to their natural consistency, and dripped down Josea’s chin and onto the smock that made up his uniform.

All of this would have to be reported, which was tiresome.

“Time a pulse,” Josea said to the nearest array.

• • • •

The go-men were headquartered in the Shell Beds on Earth’s moon. Most of those who were stationed there spent their time tending to the growth of new bivalve ships, which took hundreds of years. A few others made up the Dictate, the formal leadership of the go-men. It was to these that Josea directed his pulse.

The go-man who answered was the Erudite Admiral Alisa Sensation. Her lineless face did not betray the fact that she had been present at the launch of Blue Spring. She was one of the oldest humans alive.

“Josea Dream. Why do you disturb the Dictate?”

Josea pulsed a record of what had occurred when the nine liters of water had splashed to the floor of his bridge-cabin. Elisa Sensation’s eyes briefly flashed silver as she collected, comprehended, contemplated. She did this faster than any array that had ever been grown.

“Blue Spring was inordinately fond of Silas Enervate.” Silas had been the captain before Josea. The eremites had installed his inanimate body within Deimos, where he was communing with all the other go-men who had captained bivalve ships for so long that they became calcinated.

“I was informed of this when I took the captaincy,” said Josea. “But I was also told that Blue Spring had a history of ready acceptance of new pearl captains.”

“After a time, Captain. After a time. You have been ensconced for scarcely two decades. Blue Spring is an old ship, set in its ways.”

“So long as there no danger to the cargo or the crew,” said Josea, truculently.

Josea was the only crew.

The Erudite Admiral’s eyes flashed gold, and Josea guessed that she had entered a note to be wary of cowardice into his clays. He gave a formal nod just before the arrays at the Shell Bed cut the connection.

• • • •

Two years later, halfway to the observatory staffed by the Elderly and Alone in the Oort Cloud, Josea saw that another droplet was forming in the flesh above his station. Blue Spring had not spoken to him since the first droplet, though it had served ably and had taken on the supplies the observatory had ordered at Europa with alacrity rare in a bivalve ship of such ancient lineage.

This time, the droplet dropped when it only displaced four liters. Josea expected and accepted the alien sensations of the mercury-water worms burrowing into his brain.

I have come to admire you, Josea Dream, said Blue Spring.

“I am glad,” said Josea. “We work well together and will be in one another’s company for a long time.”

I do not believe that is true, said Blue Spring.

This disturbed Josea. “Why is that?” he asked.

Because I am dying, said Blue Spring.

• • • •

The arrays assessed for twenty-two months. They squabbled endlessly, coalitions and caucuses merging and splitting, as they attempted to come to a consensus about Blue Spring’s condition. Finally, they micro-pulsed Josea.

it is a cancer

“There is no record of any bivalve ship so afflicted,” said Josea.

there is no record of any pearl captain calcinating in such a short time as you

The dampeners in Josea’s clays were designed to keep him from shock. He felt a layer peeling away and remembered the notation of potential cowardice.

“It is far too early in my service for this to occur,” he said.

we advise pulsing the Dictate

But Josea did not.

• • • •

By the time Blue Spring reached the observatory, Josea could not stand and the great ship’s reverse acceleration was faltering. Only a mighty collaboration among Blue Spring, the arrays, and Josea himself made it possible for the Elderly and Alone to extend the observatory’s cargo net close enough to the ship for offloading.

Blue Spring had not communicated with Josea since its announcement of its impending death. Josea did not know whether the ship was aware of his quickening calcination. He still had not informed the Dictate of either circumstance.

The arrays of the Elderly and Alone communicated with those aboard Blue Spring. They had observed an unrecorded eruption of aragonite the size of a mountain on the ship’s posterior hull, straddling the hinge. They advanced the notion that Blue Spring would not be able to open unless the growth was removed.

“How do they expect us to do that?” demanded Josea.

they propose a comet

Josea thought about that for nine days before he attempted to image Blue Spring. This time, the droplet took mere hours to form, and when it splashed, it was viscous. There was an unpleasant odor to the mercury-water worms.

“The Elderly and Alone propose that we maneuver into the path of a comet and allow it to impact with your posterior hull,” said Josea.

I have been contemplating this since their arrays pulsed ours, said Blue Spring.

“Have your contemplations led to conclusions?” asked Josea.

Yes, said Blue Spring.

• • • •

The go-man who answered Josea’s pulse was not the Erudite Admiral Alisa Sensation. This was how he came to learn she had chosen, at long last, to self-calcinate.

“Blue Spring has made us aware of your circumstances,” said the Dictate go-man. “We see no other potential solution besides the comet.”

“There is another solution,” said Josea Dream.

there is another solution, said the arrays.

There is another solution, said Blue Spring.

“What do you propose?” asked the go-man on the moon.

“We propose to go beyond the galactic rim and accept our fate.”

“That is not acceptable.”

It is acceptable to us, said Blue Spring.

• • • •

And so they swam. Josea Dream, who did not like mysteries, and Blue Dream, an old ship set in its ways.

Far, far, far they swam, encountering many mysteries and many challenges to old ways. And first down the centuries, and then down the millennia, they came to revel in new ways; they came to exult in mystery.