In 2023, Detective Hasan discovers a dead body in Longharvest Lane, Whitechapel — while in 1941 and 1890, two other detectives find the same corpse.

Hasan follows new leads in the present. As Hillinghead reluctantly closes his case, Whiteman goes to desperate lengths to hide involvement in his own.

Connections between the cases start to come into focus. Whiteman encounters an unexpected complication; Hillinghead attends a séance.

Elias finally knows what it means to be loved. He creates the family he's always wanted — but Hillinghead has to suffer for it.

Across decades, the detectives work together to stop Elias from reshaping history. Will words be enough to break the loop and save thousands of lives?