While visiting a criminal in his cell, Inspector Maigret is told of a man who'd been spotted dumping a body in a Parisian canal some years ago. Later, at a popular inn, Maigret finds himself in the very place the suspected killer was last seen, and is pulled deep into a web of blackmail and deceit... A scientist is shot dead in his laboratory, his body within easy view of the surrounding apartments. Did anyone see anything? Why was he killed? Summoned to investigate, Maigret uncovers a tragic story of desperate lives, unhappy families, addiction, and a terrible, fatal greed.