Johannes Ganten, in his late 50s, known as John to his friends, leads a comfortable life as an emeritus professor. Everything has always come to him, which John takes for granted. He has never thought about anything until this morning - the Christmas holidays are just over - when he finds a note in his letterbox with the words: "Tomorrow you must die! Ganten doesn't really take the warning seriously. His old friend Peter takes a completely different view and can't understand John's attitude at all. Only the second warning and some very strange encounters gnaw away at Ganten's unshakeable self-confidence. The hours he then experiences change his life.