The railway takes centre stage as Endeavour investigates the disappearance of a local woman - with initial fears linking it to the unsolved murder of a teenager, killed several years earlier. Endeavour puts the missing woman's last known movements under scrutiny, while Thursday is absorbed in the investigation of a lorry hijack which he suspects is linked to local gangster Eddie Nero.

An assassination attempt at an international sporting event opens a new case for Endeavour and Thursday, but their investigation is quickly brought to an unexpected end. While Thursday wants to step away, Endeavour is determined to find out more, and secretly undertakes to discover the truth. He soon finds himself embroiled in the dark dealings of espionage, big business and a long-held secret that goes to the very heart of the Oxford community. While Endeavour chases down the real story behind the assassination, Thursday works closer to home, attempting to protect a battered wife from her violent husband. When tragedy strikes, Thursday has to make a tough moral decision about how to administer justice.