Paul Braconnier and his wife Blandine only have one thing in mind: to find a way to kill each other without risk. After listening to a radio show, Paul decides to go to Paris to meet a famous lawyer in the acquittal of the murderers. He tells the lawyer that he killed his wife. The lawyer asks Paul to reconstruct the circumstances of the drama. Without knowing it, he explains, in spite of himself, the way for Paul to murder his wife by putting the odds on his side to avoid death penalty or even be released.