Francis Warren (Errol Flynn) appears to have a normal life handling investments, but secretly he writes lurid detective novels under the pseudonym F.X. Pettijohn. His other career is unknown to wife Rita (Brenda Marshall) or to anyone but Inspector Mason (Alan Hale, Sr.), who mocks the books, insisting that true crime is much more difficult to solve. A man named Leopold Fissue (Noel Madison) turns up, wanting Francis to help him turn uncut diamonds into cash. Fissue's body is then found murdered on a yacht. The trail leads Francis to burlesque dancer Blondie White (Lee Patrick (actress)), who becomes his prime suspect. But her dentist, Dr. Davis (Ralph Bellamy), gives her a solid alibi. Rita becomes sure that Francis is having an affair. Blondie turns up dead, though, after asking Francis to retrieve a satchel from a locker. Rita thinks Francis must have killed Blondie, while her husband believes just the opposite to be true. The diamonds are in the suitcase. Francis concludes that only one man could be behind all this—Davis, the dentist, who promptly tries to kill Francis before the police can figure things out.