A dying man stumbles into a church and tells a young nun that he was responsible for sending an innocent man to prison. Her parish priest asks Joe Mannix, an old friend, to find out who the dead man was referring to. Mannix discovers that the dead man was a witness in a murder trial several years before -- but the man in prison, and his former attorney, steadfastly insist he was guilty. Mannix reluctantly begins to accept this, too -- until several attempts are made to convince him to stop investigating the case.
—aldanoli