Long story short:
Craig (Burr) is having an affair with Myra (Lansbury), his best friend Joe's wife. Unable to stand the guilt, and wanting to be with Myra free and clear, Craig tells Joe and asks him to divorce Myra. Joe doesn't refuse, but asks for time.
While other doings occur, Joe confronts Myra and, behind a closed door (blocking the action), a gun is fired, leaving Joe dead. Myra claims self-defense, Craig bolsters this by telling the court (at Myra's murder trial) that he and Myra are lovers and he knows Joe well enough to know he might have gone crazy and tried to attack her. Myra is found not guilty.
Later, Craig finds a letter Joe had addressed to him, but never got to send, stating Myra has been in love with an artist named Holt for years and Myra is using both Craig and Joe. After finding evidence of this, Craig confronts Myra and tells her he'll trick her into killing him, alleviating his guilt and so she'll go to prison the way she should have. In the end, he does trick her into killing him, more or less in the presence of the district attorney.
The film has all the sweaty, manic guilt you'd expect of noir, as well as a few great shots. Is it good, though? No, not really. There's not much suspense in the story since you know Craig is going to die and who will do it. The journey from points A to B is decent and both Burr and Lansbury show off more acting chops than a B movie like this deserves. That's probably why both went on to greater things while this was director Peter Godfrey's final film.
Recommended? Not really, unless you're a big Lansbury or Burr fan, but it is free to watch on the Internet Archive if you're interested.