A young man brings Inspector Torrence a message he found in a bottle drifting on the Seine. It is a desperate call; an old man is sequestered in an abandoned mill that water is gradually invading ... The O Agency is investigating ...

In order to be able to touch the heritage of Chauffier-Mignot; Jean Dassonville wants to marry Cécile the daughter of the family. The father not agreeing, he decides to kidnap him and lock him up in an old water mill. But Chauffier-Mignot refuses to sign the marriage authorization and even succeeds in sending a message in a bottle thrown into the river ...

Agency O is commissioned by an insurance company to investigate a series of burglaries that the police attribute to a black jacket that moves on a powerful motorcycle. In his office, Inspector Torrence is examining an object he found, during an investigation, in a jewellery store and whose nature and function are difficult to specify. Then a young brunette girl enters who comes to entrust Torrence with an important document. When the young girl leaves the agency, the object has disappeared...

A series of tragic coincidences led the team of the O Agency to investigate in Montigny-sur-Long where, in two inns in the region, two blind travellers were strangled in two rooms, each bearing the number 9. For eight days, the official police are trampling. For fun, Emile begins to research. Torrence moves to the Auberge de la Vane-Rouge. Barbet photographs the clients ...