Chatelard, one of Viscount de Kerlec's guests, has died in mysterious conditions. The police initiates an investigation and sends detective-inspector Pauc to de Kerlec's manor. Pauc decides to mingle with the viscount's guests , who are all likely to have committed the murder. Among them, there is Jacques Mauclerc, a naval officer, and a seedy character named Bartoli, in fact a spy in search of secret documents. Pauc will end up untangling the web during a dramatic séance.

A specialist in the fight against cancer, a young doctor finds himself suffering from a terrible illness.

Mony, fiancée of Jacques, adopts the child he had with Gisèle. When she wants to take it back, she gives it back to him and pushes Jacques to marry her.