Hervé Carpentier, a 43-year-old horse breeder, was found dead in Paris, killed by a hypodermic arrow in the middle of the jugular jugular. One of his stallions has also disappeared. Alice and Marquand go to the stud farm where the victim was working. They collect the testimony of one of his colleagues and announce the news of his death to his wife. Many grey areas surround the provenance of the missing horse.
