In 1905 Hungary, a young village woman has just undergone a marriage to the spoiled son of a man to whom her father is indebted, in order that the debt be cancelled, only to be spirited away by her true love, a young peasant, by whom she soon becomes pregnant. Together they attempt to find a way to buy up her father's debt and also pay for a divorce from her husband, against various odds.

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".