To open this cage is to unleash a monster . . .



Detective Phil Brennan is called to a derelict house on the edge of Colchester. The place looks empty. But someone still visits after dark. Detective Phil treads the rotten stairs down to the cellar—where he comes face-to-face with the most horrifying sight of his career.



A cage, built entirely from human bones. And a feral child trapped inside.



The boy gazes up at Phil in wild-eyed terror, half-starved, and too traumatized to speak. The remains, strewn across the floor, reveal he's not the first to be caged this way.



And his captor is determined he won’t be the last. No one escapes the cage of bones alive.



There's no going back for Detective Phil and his profiler partner, Marina Esposito. The race is on to solve the case, and escape the killer's ever-tightening snare . . .