Teacher Paul Pressett is trapped in a loveless marriage to Eleanor. He has fallen in love with fellow teacher Myra Bawne but when Eleanor's health deteriorates, she quits her job. Believing they'll never be together, Paul decides to act.

Eleanor tells Bessie Furle she has found a love letter Paul was writing to Myra. Eleanor's health takes a down turn and dies. Paul and Myra plan to marry but gossip reaches the police. Chief Insp. Boltro thinks murder and exhumes the body.

Paul and Myra go on the run and head for Eastbourne but find their pictures on the front of the newspaper. The autopsy on Eleanor's body finds traces of arsenic so Boltro wants an arrest. Myra asks Paul about the arsenic tin in the garden.

Paul and Myra change their identity after discarding her easel and handkerchief in a forest. Paul is now calling himself Rev. Mark Calforth but his body is struggling. They reach Fell Country but Inspector Boltro's men are now closing in.

Paul Pressett and Myra Bawne are put on remand waiting trial. It is decided that Sir Hayman Drewer with prosecute defendants in both cases while will Sir Kenneth Eddy act for the defence. He is sentenced to hang but will Myra be spared?