No two criminals are alike, and Quinn knows this more than most. After months of stress and pleading, his study has been approved. His participants all reside under one roof: Greenwood Prison.

The men sitting opposite him have done awful things, but Quinn's not there to judge; he's there to work through a psychopath checklist.

He needs psychopaths for his study, and one participant fills him with more unease than the others.

Zane Black wears many faces, and Quinn has a hard time finding the real man behind the masks. He flirts, he manipulates, and boasts. He's clever and takes control of their sessions. With all Quinn knows about psychopaths, he can't stop his heart being seduced by this one.

When the study finishes, will Zane let Quinn go and move on, or will he leave Quinn with more questions?