Inspector Maigret is sent to Antibes, on the French Riviera, to investigate the murder of William Brown, a wealthy Australian living in semi-exile. Brown was found stabbed to death in a villa just inland from the coast. But nothing about the case feels urgent — or clear.

Inspector Maigret receives an urgent and discreet summons from Minister Auguste Point, the Minister of Public Works. A highly confidential document — a memo concerning a major public health scandal — has disappeared from the minister’s office. Its contents, if revealed, could destroy reputations and bring down the government.

On his way to take a short holiday in the southwest of France, Maigret boards an overnight train to Bergerac. Sharing the compartment with a silent, nervous stranger, Maigret becomes suspicious of the man’s strange behavior.

Just before bedtime, Maigret receives a phone call — not an official summons, but a personal appeal from a man named Doctor Charles Richet, a well-respected country physician. Richet tells Maigret he believes he’s about to be arrested for the murder of his wife, and that the local police are making a mistake.

At a lonely crossroads outside Paris, known as Three Widows’ Crossroads, a Dutch diamond dealer, Isaac Goldberg, is found murdered in his car — shot through the chest, slumped at the wheel, the car left parked in the garage of a nearby house.

Maigret is surprised — and a little uneasy — when Léon Florentin, a man he hasn’t seen since childhood, suddenly walks into his office at the Police Judiciaire. Florentin, once a charming dreamer, is now a shabby and nervous middle-aged man who claims he’s in serious trouble.

Inspector Maigret is summoned to the quiet village of Saint-André-sur-Mer, on the Atlantic coast, after a local schoolmaster, Joseph Gastin, is accused of murdering an unpopular widow, Louise Sabatier. She was shot in the back through a window with a rifle — and the whole village seems quick to blame Gastin.

Maigret is called to investigate the murder of Léonard Lachaume, a bitter, aging man and heir to a once-prominent biscuit company now in decline. He was found shot in his family’s decaying home, surrounded by reluctant, tight-lipped relatives.

When the elegant but emotionally distant Madame Nathalie Pardon arrives at the Police Judiciaire, she reports her husband, Gérard Pardon — a prominent Parisian lawyer — missing. She refers to him mockingly as "Monsieur Charles", a name he apparently uses during his mysterious late-night excursions into Paris nightlife.

Maigret is immediately struck by the woman’s coldness, her too-slick story, and her aristocratic detachment. She barely pretends to care. So why report him at all?

In the early hours of the morning, a young woman’s body is found lying on the cobbled banks of the Seine River in Paris — strangled, discarded, and unnoticed until death. She is eventually identified as Louise Lamboing, a quiet girl from the provinces who had recently come to Paris.

There are no immediate suspects. No one seems to know her well. No motive stands out.