Something dark is lurking in the Louisiana bayou. A methodical killer with a taste for medical experimentation is hard at work completing his most harrowing crime yet, while the authorities desperately try to catch up. Forensic pathologist Dr. Wren Muller is the best there is. Armed with an encyclopedic knowledge of historical crimes, and years of experience working in the Medical Examiner's office, she's never encountered a case she couldn't solve. Until now. As case after case piles up on Wren's examination table, she is sucked into an all-consuming cat-and-mouse chase - led by a brutal murderer, who is getting more brazen by the day.