Karli (12) moves to the Alps, where his parents fulfil their dream of owning a hotel. Instead of vacation, Karli grudgingly helps his parents scrape off old wallpaper. Then he discovers that he can travel through time with the old elevator – to the year 1938! There, Karli befriends the lively Jewish girl Hannah and the shoeshiner Georg. In the present, Karli gradually confronts the shadow of National Socialism that looms over the world of his new friends.
When Georg is wrongfully accused and arrested for theft, Hannah and Karli want to find the real criminal. They discover during their investigations that strange things are happening in the hotel. The three friends want to solve the mystery together and embark on an exciting journey, during which they discover that a great secret lies behind the hotel facade!