Maigret is called to the high-class Hotel Majestic to investigate a body. The wife of a wealthy American has been killed - but to Maigret's surprise she has a gun in her purse. He begins to follow up the handful of clues that could explain her secret life and her demise.

Captain Justin Mollenard works for a company that sells armaments to the Far East. After an eventful stay in Shanghai, where he and his cargo are the victim of a malicious attack, he returns to his hometown of Dunkirk. Mollenard receives a frosty welcome from his wife Mathilde, who resents the way in which he has neglected his family for so many years. Mollenard’s only wish is to get back to sea as soon as he can, but a sudden heart-attack leaves him paralysed and entirely in his wife’s power...

Willy Ferrière is a gambler living beyond his means, and his mistress is as greedy as he's dead broke. One day, he says out of loud in a a Montparnasse café that he would give 100,000 francs to get rid of his wealthy aunt so he could claim his inheritance. Someone secretly lets Willy know it's a deal. The old lady is murdered, and a low-life criminal is manipulated to be the perfect suspect. But Superintendant Maigret feels something is wrong.