Nikki makes a breakthrough, but can the team believe everything they are told? The Lyell is compromised in an unexpected way as the team strive to find out who the man on the beach was and why he was killed. In a dark and chilling story, they must unite to discover the truth and, above all, trust no-one.

Nikki continues to try to identify the last of the remaining bodies, in an effort to uncover any connections and find a motive, while Jack and the police begin to look into several two-decade-old missing-persons cases in the hope that they might reveal the identity of the man dubbed ‘The King's Cross Serial Killer'.