Each story follows the dedicated team of forensic pathologists who try to work out how and why the victim died, often risking their own lives in the process. In this series: an apparent suicide that starts to look a lot more like murder, a young woman is dragged from a river in the same spot where her best friend mysteriously disappeared three years before and, in the final explosive story set in Mexico, Nikki finds herself in danger when she searches for the truth about the death of a former colleague.