Brighton based Detective Superintendent Roy Grace is a hard-working police officer who has given his life to the job, but his career is currently at rock bottom. He’s fixated by the disappearance of his beloved wife, Sandy, and running enquiries into long forgotten cold cases with little prospect of success. Following another reprimand for his unorthodox police methods, Grace is walking a career tightrope and risks being moved from the job he loves most.

A veteran beat cop and teenage girl fall to their deaths from a tower block in south-east London, leaving a five-year-old boy and rookie police officer Lizzie Griffiths on the roof, only for them to go missing. Detective Sergeant Sarah Collins is drafted in to investigate, working to find Lizzie before she comes to serious harm, but also to uncover the truth behind the grisly tower block deaths.

A grief-stricken man leaves a rehab clinic to seek vengeance after he discovers the man responsible for his wife's death has been released from prison.

Mystery Island hosts a corporate retreat with a guest being Emilia's ex-fiancé. Old feelings become complicated, tensions run high, and allegations arise when a guest is found dead.