Once a regular cop, Choucas now works as a private investigator, using methods his former colleagues would revile him for. One day, he receives a visit from an old lady, Madame Pigot, who asks him to look into the disappearance of her blind daughter. Choucas accepts the apparently anodyne case but soon finds he may be in for more than he bargained. First he is assaulted by a mysterious stranger and then Madame Pigot is shot dead just before she can give him vital information relating to her daughter. Then, when he is set up for killing a police commissioner, Choucas realises that he has been caught up in a very deadly game of cat and mouse. But who are his opponents and why are they so keen to have him killed…?