A killer arrives in Avoca, Oklahoma, where he marks two murder scenes using skin from a dead man’s thumb dipped in the victim’s blood. He poses as a Texas Ranger and takes refuge in the home of a pastor-friend to get close to his next target.

Subtleties in clues thrusts Detective Mike Canyon into a contest he refuses to lose: identify and nab the murderer or lose his wife Sunday at midnight. Officer Shannon Roe – who unbeknownst to Canyon is the killer’s sister – receives a promotion and aids Canyon on a trail of kidnapping, poisoning, and ultimate clash with the killer.