Howard, a well-known book publisher, is concerned for his wife, Joanna. Since returning from the country, she has become unusually distressed, nervous and mysterious. The play takes a sinister turn when Howard arrives home to find Perry, a former friend, has been shot by Joanna in a struggle. She admits that Perry has been blackmailing her and, to protect her, Howard confesses to the shooting. Perry dies before the police can question him thoroughly and, after a second attempted murder, Howard is the centre of a complex investigation where no-one is blameless.