In the long-running, hit BBC crime thriller, forensic pathologist Dr. Samantha Ryan risks her career and her life in four murder cases that hinge on grisly but confusing evidence. Did a Cambridge college professor die of head injuries or suffocation? Did a teenager perish at the hands of her lover or her stalker? Was a farmer's gruesome death an accident or retribution? And how to stop a drugs war if police are selling the drugs?