The middle of the night. Sam Dryden takes a call from an old friend from his days in the military. She needs his help. Urgently. There's no further explanation.

Two hours later, Dryden and his former teammate smash their way in to a remote desert shack. Inside they discover four young girls, caged and threatened with death by their abductor. Dryden acts.

But how had Dryden's friend known what about to unfold? Why was it so important that they flee the scene before the police arrive? Only one thing is certain: Dryden is now facing a ruthless enemy that always seems to be one step ahead.