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.
Hubert Hrabe, known as Smart Boy, is a Prague dandy who is always skirting the edge of the law. Like every likable rogue, he has a worthy adversary - Police Inspector Mourek, who has long been trying in vain to put him behind bars. However, this defender of justice, who is constantly trying to outsmart his "own" criminal, ends up becoming the victim of his own zeal while hunting forgers that are as good as any in Europe, as Hubert the Smart Boy, sets a trap for Mourek
