The celebrated actor considers his wife a nitwits actress of a mediocre talent. But an influential playwright, a friend of theirs, has written a play with the main role designed for her, Kati, particularly. Its title is "The Most Intelligent Woman in the World". On the day of the first night performance Kati recalls their past, the times she had together with her husband.

There are mysterious murders in the area of ​​Lake Balaton. These places are shrouded in secrecy and constantly attract hunters: during the Second World War, the Germans had hidden a huge treasure here. Investigation of the murders entrusted to Major Kardos. He takes up the case, but in search of treasure he had many competitors. Kardos uses help from his loyal friend - a policeman-superman Etvash aka "Droplet".