Tomasz Karwatka

Twelve-year-old Tomek helps his father working at a gas station. His dream is to own one of the cars that he and his father service every day. Tomek is also in love with Mariola, a girl from Warsaw. She, in turn, has feelings for Wojtek.

As a result of a mistake, the siblings change roles and go on vacation somewhere else than planned. The boy goes to his aunt and cousins, the girl goes to her uncle and cousins. To save her brother, the sister pretends to be a boy and he, left with no choice, pretends to be a girl.

World War II. The Germans enter Sosnowiec, which complicates the relationship between the three friendly children.