“Low-light camera better,” Altantsetseg said. “Upgrade. Might work.” She was already maneuvering the little submarine out of the ship. Its cameras moved across the crusted hull, blurred by sea life, becoming nothing more than a reef and sea caves.

“When I was a child,” Dr. Mínervudóttir-Chan said, “I was fascinated by shipwrecks. What could be more interesting than these strange artifacts we create, these unintended consequences of our efforts to cross a medium totally hostile to us? These vessels filled with all our hopes for exploration, trade, war. These ships filled with all the good and evil of our society, being transformed back into nature.”

“Weird kid,” Altantsetseg said. “Need play outside more. Need friends.”

“We’ve scattered the bottom of the world’s oceans with our drowned hopes,” Dr. Mínervudóttir-Chan continued. “I wonder what these creatures can possibly understand of us. They are living in this artifact of ours, filled with the flooded traces of our industry and life. What do they make of it?”

“Better to ask,” Evrim said, “what they make of the nets and spears that murder their friends and family. Or whether they know humans eat them.”

The submersible arced down into the dark rectangle of the hatch.

Ha found herself thinking of a human settlement as seen from the water just offshore—lights along the beach, the sound of laughter. A fire in the sand lighting alien, hungry faces.

The camera adjusted. This space was smaller—a galley or barracks. It was hard to tell from the blurred outlines of objects. It was dark in here—too dark for the submersible to make out much. Then, rotating, it picked out a shape.

“There,” said Ha.

“I see it,” said Altantsetseg.

A slow, pale form, moving along the bulkhead. Its skin had gone white, with only patches of rusty color remaining here and there. Two of its arms were missing.

“Hold here.”

As they watched, the old octopus pushed upward through the water with a series of jets, moving out of the hatch. Altantsetseg turned the submersible to follow it. The octopus crawled along the hull of the freighter, up from the galley deck to the wheelhouse, where it compressed itself through a missing window.

“Can we follow it?” asked Dr. Mínervudóttir-Chan. “Can we fit through there?”

“Tight,” Altantsetseg said. “And current here. Hard to fornicating maneuver. But try.”

The submersible swung down toward the window of the wheelhouse. As it passed through, struggling against the current, its side thumped against the frame, hard. But Altantsetseg managed to right it inside the space.

There was good light here—sunlight through the clouded plexiglass of windows still intact. But it was difficult, at first, to understand what the submersible’s cameras picked out.