When Chief Constable Bligh accompanies her friend Diane Tulliver home to Dysart Hall after a night at the opera they arrive to a horrifying scene. Diane's husband Paul has been shot dead and ex-convict Charley Mirren is standing over him bearing a gun. It appears to be an open-and-shut case for Jessica Blight, but as she and her colleague Inspector Fremont probe further they discover all is not what it seems. Through a series of flashbacks and re-enactments of the events leading up to Paul's death, we soon find it is not just the murderer's identity that is in question.