You're a good soul, inspector, and when you're up against the second-rate criminals you get here in Paris, you're a crack policeman. But this business isn't for you. These guys play rough and they may hurt you. Just drop it! What concern is it of yours, anyway?'

When Maigret learns that his hapless colleague Inspector Lognon is being menaced by some notorious American mobsters, he makes it his mission to bring them to justice - despite threatening warnings that he is out of his depth.