Surprised by the fog, the ship Fraternité suffered significant damage. Therefore, an investigation must be carried out in order to determine the conditions under which the incident occurred. It falls to deputy Puy-Pradal who has just been appointed high commissioner of the navy: the latter, after his meeting with an actor, gradually forgets the mission entrusted to him.

An ex-French Foreign Legion soldier comes to Soho and ends up as a singer in a cafe.