2049. Earth's prisons are shut down and all inmates placed in massive hibernation tanks. In the ten years since then, no one has broken out…until now.

When prisoners check into Washington D.C.'s maximum security "sugar cube," they don't check out. Here lie suspended not just the planet's most dangerous criminals, but also half a million so-called "center inmates"—troublesome activists whose only offense is to challenge those in power.

Laurel Cole was one of those inmates—and now she's on the run. After pulling off a meticulously executed escape plan, she and her team must elude the police by descending into the tunnels that run like poisoned veins beneath the city. Pursued by a ruthless mercenary who knows these sewers better than anyone, Laurel seeks help from a group of renegades who live huddled in the fetid darkness. But if she ever hopes to see daylight again—and expose the government's lies—she'll have to go even deeper. . . and the clock is ticking.