While celebrating his birthday, police inspector Basquier recalls two of his most celebrated cases. The first involves duplicitous moneylender Olga. The second concerns the brutal broad daylight murder of innocent young Yvonne.

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.

Au Royaume des Cieux takes place in in a dreadful girls' reformatory. A couple of lovers will try to escape from this living hell.