Jackie finds the body of her nine-year-old pupil, Cefin, seemingly drowned. The discovery revives the ghost of an unsolved cold case that rocked the town three years prior.

Old accusations resurface as Jackie and Bull must put aside years of mistrust before the town's tensions ignite into violence.

With the town turning on itself as long-buried secrets emerge, Jackie and Bull's fragile partnership is tested by a new discovery.

Jackie struggles after her estranged sister returns and reignites years of guilt and betrayal, while Bull finds himself faced with two cases that are undeniably linked.

Rising floodwater cuts Morfa Halen off from the world as another body is discovered, with Bull closing in on the truth behind an illegal operation at the heart of all three cases.

During a unhappy storm, the residents of Morfa Halen form a search party, and Jackie and Bull discover the horrifying truth behind the crimes haunting the town.