Neco je ve vzduchu (1981)

The urn supposedly containing the remains of Alice's grandfather falls out of the window and breaks. To Alice's great surprise, the urn is empty and the girl learns that the grandfather didn't die but disappeared under mysterious circumstances on the 2nd September 1946 in the town of Telc. Her grandmother claims that a mysterious young man with dark glasses was implicated in her husband disappearance. Alice is determined to solve the mystery. Grandmother's story leads Alice to a shoemaker who hands her Professor Jeník's - her grandfather's - invention, called the Force-fields Accelerator. Alice tells her boyfriend Petr about the device and the young man creates a time machine following the professor's instructions. The young couple then travel back to 1946 and there they indeed meet Alice's grandfather, and his daughter Blanka, who will later be Alice's mother.