Maigret runs into the tough methods of American gunmen when mafia gangsters arrive in Paris to carry out a hit on an informer.

When a rich old woman is murdered with no apparent motive, all fingers point to the delivery man. Maigret isn't so sure and sets out to find the real murderer

Tomorrow a man must die on the guillotine, unless Maigret can demolish the case he himself built up against him.