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.