When Phoenix probation officer Casey Carson goes to work, she expects naked people to answer doors, meth-addicted clients to hit on her, and angry judges to chew her out in court. After a routine home visit with a client, a Diablo gang member, goes horribly wrong, she knows she must watch her back. Even she must admit that a one-eyed, bad-ass, angry gangster and his crew gunning for her is a bit more than she was trained to handle.

Casey has even more reason to fear Diablo when her cousin Hope goes missing, and it looks like their handiwork. With women vanishing at an alarming rate in the area, police treat Hope's disappearance as a priority. Still, Casey can't sit on the sidelines, even with her ex-husband leading the investigation. After she receives information that proves her suspicions about Diablo right, the gang will do anything to keep her from sharing it with police, even if that means taking her on a one-way trip to the desert.