Kent, May 1941. The towns and countryside south of London continue to take a battering from German bombers. Canterbury, with the focal point of its distinctive cathedral, is among the hardest hit.

The landmark and holy site is the scene of further tragedy when Canon Walter de la Coeur is found savagely bludgeoned to death on the exact spot where Thomas Becket also met his end centuries before. Detective Chief Inspector Coburg and Sergeant Lampson are called in from Scotland Yard and must sift through the dead man's responsibilities for the cathedral's finances, as well as his private life. But their quest to find the killer is hampered when the deadly force of the Blitz strikes very close to home.