Maigret goes to a small village after receiving a letter from the son of the schoolteacher. The schoolteacher is currently in prison awaiting trial for the murder of the village's postmistress. She was supposedly killed when he was out of the classroom for a few minutes one morning collecting graded essays from his house which is attached to the school. The schoolteacher is an outsider in a very insular community. Maigret investigates a collection of drunks and children to find the truth.

A count who is also a diplomat is murdered.

After receiving some threatening anonymous letters, an old classmate of Maigret wants him to investigate. Then, the classmate is killed.

A man finds a note signed Picpus written on a piece of blotting paper. Picpus says he is going to kill a fortune teller. And sure enough, a fortune teller is found murdered.