He studies the schematic on his dashboard. A reflected fingernail of light traces his profile.

He turns his squid to port. "This way. Keep to the bottom."

They edge closer to the light, keeping it to starboard. The glow expands, resolves, reveals an impossibility: a lake at the bottom of the ocean. The light shines from beneath its surface; Clarke thinks of a swimming pool at night, lit by submerged spotlights in the walls. Slow extravagant waves, top-heavy things from some low-gravity planet, break into shuddering globules against the near shore. The lake extends beyond the hazy limits of rifter vision.

It always hits her like a hallucination, although she knows the pedestrian truth: it's just a salt seep, a layer of mineralized water so dense it lies on the bottom of the ocean the way an ocean lies at the bottom of the sky. It's a major selling point to anyone in search of camouflage. The halocline reflects all manner of pings and probes, hides everything beneath as though there were nothing here but soft, deep mud.

A soft, brief scream of electronics. For the merest instant Clarke thinks she sees a drop of luminous blood on her dashboard. She focuses. Nothing.

"Did you—?"

"Yes." Lubin's playing with his controls. "This way." He steers closer to the shores of Impossible Lake. Clarke follows.

The next time it's unmistakable: a brilliant pinpoint of red light, laser-bright, flickering on and off within the jagged topography of the dashboard display. The squids cry out with each flash.

A deadman alarm. Somewhere ahead, a rifter's heart has stopped.

They're cruising out over the lake now, just offshore. Roiling greenish light suffuses Lubin and his mount from below. A hypersaline globule shatters in slow motion against the squid's underside. Light rising through the interface bends in odd ways. It's like looking down through the radium-lit depths of a nuclear waste-storage lagoon. A grid of bright pinpoint suns shine far below that surface, where the surveyors have planted their lamps. The solid substrate beneath is hidden by distance and diffraction.

The deadman alarm has stabilized to a confidence bubble about forty meters straight ahead. Its ruby icon beats like a heart on the screen. The squids bleat in synch.

"There," Clarke says. The horizon's absurdly inverted here, darkness overhead, milky light beneath. A dark spot hangs at the distant, fuzzy interface between. It appears to be floating on the surface of the lens.

Clarke nudges her throttle up a bit.

"Wait," Lubin buzzes. She looks back over her shoulder.

"The waves," Lubin says.

They're smaller here than they were back near the shore, which makes sense since there's no rising substrate to push the peaks above baseline. They're rippling past in irregular spasms, though, not the usual clockwork procession, and now that she traces them back they seem to be radiating out from…

Shit