Episode 1

S1 E1: After 11 years absence away from the force, DS Marcella Backland finds herself drawn back to police work following the return of the Grove Park Killer, her last case before she left to start a family. In 2005, the killer tied the victims' hands and feet with cable ties before taping a plastic bag around their heads. The case went cold. But now, over ten years later, it seems he has returned. Marcella is driven by the news that her previous lead suspect, Peter Cullen, is out of prison for manslaughter and now working in a bakery on a prison placement scheme. But nobody else on her team thinks it could be Peter, and Marcella's lone wolf approach quickly alienates her new colleagues. But Marcella's also pre-occupied with the breakdown of her 15-year marriage to Jason Backland. It's a huge blow to her when he tells her he no longer loves her. She believed they were happy.