An historical depiction of the events preceding the political murder of Archduke Franz Ferdinand, would-be emperor of the Austro-Hungarian throne, in Sarajevo on June 28th, 1914.

The bank officer Bedrich Hroch is sent by the bank director to the zoo, which asked an allocation of one and half kg of gold for a gold tooth for a hippo. During the check up of the hippo's teeth Bedrich is swallowed by the hippo. The man does not die in the hippo's guts and he chats quite happily with his frightened wife Dása. Journalist Pip Karen, his friend is also present to the dialogue and he has immediately an idea how to use this special situation. He tells to the new minister Borovec and his opponent professor Fibinger that there is a hippo in the zoo which can speak. He also tells them how to use this situation for a political propaganda.

Jan Zika is the legendary hero of the communist resistance movement during World War II and leading functionary of the second underground Central Committee of the Communist Party of Czechoslovakia.