An anonymous note to the police reports that a body has been burnt in the furnace of the bookbinder, Frans Steuvels, on the Rue de Turenne. Preliminary investigations turn up suspicious details, and two human teeth are found in the furnace, of a man who'd been alive not long before. Steuvels is held in custody. Meanwhile Mme Maigret has had a strange experience while waiting for her dentist appointment. A woman she had often met on the bench while waiting, with a young child, suddenly leaves the child in Mme Maigret's care and disappears for over an hour, returning to take the child and disappearing without explanation