Twenty meters from the surface. The water ahead darkens suddenly, as though an eclipse were in progress. An instant later that darkness resolves into the toe of a giant: the rounded end of a cylindrical structure half-buried in drifting sand, fuzzed with sponges and seaweed, curving away into the hazy distance. Nav pegs it at eight meters high.

"I thought it floated," Clarke says.

Lubin pulls back on the stick: Phocoena climbs into the water alongside the structure. "They beached it when the well ran dry."

So this great sunken pontoon must be flooded. Girders and struts stand on its upper surface, a monstrous scaffold rising into daylight. Lubin maneuvers the sub between them as though threading a needle. Nav shows them entering a submerged arena enclosed by four such structures arranged in a square. Clarke can see their dim outlines through the water. Pylons and trusses rise on all sides like the bars of a cage.

Phocoena breaks the surface. The outside world ripples as water sheets down the acrylic, then wavers into focus. They've come up directly beneath the rig; its underbelly forms a metal sky a little less than ten meters overhead, held from the earth by a network of support pylons.

Lubin climbs from his seat and grabs a fanny pack off a nearby utility hook. "Back in a few minutes," he says, popping the dorsal hatch. He climbs away. Clarke hears a splash through the opening.

He still isn't happy about her presence here. She ignores his safe-distancing maneuver and rises to follow.

The air wafting through the hatch blows cold against her face. She climbs onto the sub's back and looks around. The sky—what she can see of it, through the girders and pylons—is gray and overcast; the ocean beneath is gunmetal to the horizon. But there are sounds, behind her. A distant, pulsing roar. A faint squawking, like some kind of alarm. It's familiar, but she can't quite put her finger on it. She turns.

Land.

A strip of sandy shore, maybe fifty meters past the jacket of the rig. She can see tufts of weathered, scrubby brush above the high-tide line. She can see moraines of driftwood, pushed into little strips along the beach. She can see surf pounding endlessly against it all.

She can hear birds, calling. She'd almost forgotten.

Not N'Am, of course. The mainland's still a good two or three hundred kilometers away. This is just a way station, some lonely little archipelago on the Scotian Shelf. And yet, to see living things without either fins or fists—she marvels at the prospect, even as she marvels at her own overreaction.

A steep metal staircase winds around the nearest pylon. Clarke dives into the ocean, not bothering with hood or gloves. The Atlantic slaps her face, a delicious icy sting across her exposed skin. She revels in the sensation, crosses to the pylon with a few strokes.