The main character of the story is Professor Trojan, the head of a Prague clinic, who is not experiencing the happiest of times. His cat has been poisoned with cyanide, he has a falling out with his son Petr, who has moved to Brno to be with his wife, the promising singer Eva, and only seeks out his father when he needs money, and as if that weren't enough, someone shoots him in the evening. Trojan initially considers it a mistake or a prank and does not share the fears of those around him. But ...