Inspector Maigret is supposed to be working to stop the gangs of robbers terrorising Paris, but then a body is found, dumped in the Bois de Boulogne. It turns out to be a quiet, likeable burglar he has known for years, and for whom he cannot help feeling affection. Defying orders from his superiors, he determines to discover who killed his old acquaintance – even if it leads him into terrible danger.