"I don't know. Who else is out here?"

"Mike. Lenie." Lubin's voice, faintly, from somewhere ahead.

Clarke looks at Brander. Brander looks back.

"Right here," Brander calls, edging his volume up.

"I found it," Lubin says, invisibly distant.

Clarke launches off the bottom and grabs her squid. Brander's right beside her, sonar pistol out and clicking. "Got him," he says after a moment. "That way."

"What else?"

"Don't know. Big, anyhow. Three, four meters. Metallic."

Clarke tweaks the throttle. Brander follows. A riot of fractured color unspools below them.

"There."

Ahead of them, a mesh of green light sections the bottom into squares.

"What—"

"Lasers," Brander says. "I think."

Emerald threads float perfectly straight, a luminous profusion of right angles a few centimeters off the bottom. Beneath them, drab metal pipes run along the rock; tiny prisms erupt at regular intervals along their length, like spines. Each prism, an interstice; from each interstice, four beams of coherent light, and four, and four, a wire-frame checkerboard overlaid against bedrock.

They cruise two meters over the grid. "I'm not sure," Brander grates, "but I think it's all just one beam. Reflected back across itself."

"Mike—"

"I see it," he says.

At first it's just a fuzzy green column resolving out of the middle distance. Nearness brings clarity; the beams crisscrossing the ocean floor converge in a circle here, bend vertically up to form the luminous bars of a cylindrical cage. Within that cage a thick metal stalk rises out of the seabed. A great disk flowers at its top, spreads out like some industrial parasol. The spokes of laser light stream down from its perimeter and bounce endlessly away along the bottom.

"It's like a— a carousel," Clarke buzzes, remembering an old picture from an even older time. "Without horses..."

"Don't block those beams," Lubin buzzes. He's hanging off to one side, aiming a sonar pistol at the structure. "They're too weak to hurt you unless you get it in the eye, but you don't want to interfere with what they're doing."

"And that is?" Brander says.

Lubin doesn't answer.

What in the world— But Clarke's confusion is only partly directed at the mechanism before her. The rest dwells on a disorienting sense of alien cognition, very strong now, not her, not Brander, but somehow familiar.

Ken? That you?

"This isn't what we saw on sonar," Brander's saying. Clarke feels his confusion even as he talks over it. "Whatever we saw was moving around."

"Whatever we saw was probably planting this," Lubin buzzes. "It's long gone by now."

"But what is..." Brander's voice trails down to a mechanical croak.

No. It's not Lubin. She knows that now.

"It's thinking," she says. "It's alive."

Lubin's got another instrument out now. Clarke can't see the visual readout but its telltale tic tic ticking carries clearly through the water.

"It's radioactive," he says.

* * *

Alice Nakata's voice comes to them in the endless darkness between Beebe and the Land of the Carousel.