Happy Valley is a dark, funny, multi-layered thriller revolving around the personal and professional life of Catherine, a dedicated, experienced, hard-working copper. She is also a bereaved mother who looks after her orphaned grandchild.

Bjørn investigates the killing of his daughter. People around him believe she might have committed suicide, but he doesn't accept that. Both the stakes and the suspense rise relentlessly as Bjørn inches closer to the truth.