Robert Mackay, an Australian interested in race cars, is in Paris to look for his aunt who may have been in the French Resistance and may be dead. In fact, she is dead, and in a bar that evening, while absorbing the fact, Mackay witnesses the murder of a man and grapples with the murderer. Since he is the only serious eyewitness, the police keep him in Paris to help find the murderer. When the man who was murdered turns out to be a distinguished Algerian political figure and the murder, presumably Algerian as well, sends the police a letter threatening to infect the city's water supply with cholera, this visit to Paris takes longer and becomes even more dangerous and suspenseful.
Robert Mackay, an Australian interested in race cars, is in Paris to look for his aunt who may have been in the French Resistance and may be dead. In fact, she is dead, and in a bar that evening, while absorbing the fact, Mackay witnesses the murder of a man and grapples with the murderer. Since he is the only serious eyewitness, the police keep him in Paris to help find the murderer. When the man who was murdered turns out to be a distinguished Algerian political figure and the murder, presumably Algerian as well, sends the police a letter threatening to infect the city's water supply with cholera, this visit to Paris takes longer and becomes even more dangerous and suspenseful.