Preparing to leave for their annual vacation in Alsace, Maigret gets a letter from an old school friend, Jorissen, who'd become a teacher in Quimper. A former student of his, Pierre Le Clinche, had sailed as a radio operator out of Fécamp on the trawler Océan. When they'd returned to port, the captain, Octave Fallut had been killed, and Le Clinche was being held. Maigret convinces his wife that they should take their holiday in Fécamp, where he can unofficially investigate. Upon arrival, he meets Jorissen and Le Clinche's fiancée, Marie Léonnec. Maigret goes to the café, Au Rendez-Vous des Terre-Neuvas, where all the sailors hang out.
The voyage of the Océan was spoken of as strange and ill-fated from the first. A sailor had fallen and broken a leg before they departed, and on the third day, a young cabin boy, Jean-Marie Canut, his first voyage, had been swept overboard. Even the catch had been poorly salted, and was half worthless. Maigret learns the captain had had a mistress, a young woman of questionable repute, Adèle Noirhomme, whom he saw at Yport where he'd gone to question the chief engineer. No one wants to tell anything, and Le Clinche is totally depressed and refuses to talk. Maigret discovers that Adèle had been on board during the voyage, and that Le Clinche had slept with her.
After a confrontation between Adèle, Le Clinche, and her boyfriend, Gaston Buzier, Maigret has them all released. But Le Clinche shoots himself, and is rushed to the hospital. Maigret goes on board the ship, thinking over the events, and realizes that the cabin boy's death had been the catalyst. He visits Le Clinche in the hospital and learns that the captain had accidentally killed the boy and thrown him overboard. Le Clinche had told the boy's father on arrival at Fécamp, and the father had killed the captain. Maigret leaves things as they are, and hurriedly returns to Paris.
This report prepared by Dana Samson