While assisting the police elsewhere in France, Maigret becomes unofficially involved in a missing persons case involving the husband (Marcel Blanc) of a young woman (Germaine Blanc). She's trying very hard to find her husband who has disappeared under mysterious circumstances, but she is very reticent when speaking about it to Maigret. As he follows her and finally gains her partial trust, the plot begins to expand to include stolen paintings, crooked boxing and a fence who turns out to be Germaine's father.

When the wealthy owner of a pharmaceutical company is shot and killed at his desk with a plundered safe behind him, Maigret wonders if it was just a robbery gone wrong. Whatever it was, he's convinced the answer lies down the block, where the victim's ex-wife and her husband, his girlfriend and his wastrel son all live.

A man is killed in a hotel in Paris. Maigret meets there a young woman who says she is a prostitute. But it seems to Maigret she is not what she wants him to believe... This seems to become the very last Bruno Cremer's Maigret.