A series of stupid coincidences causes the young Munich painter Paul to convert his uncle's castle into a hotel for four weeks. But he can't complain: business is good and he has plenty of guests. For exmple, there's Theo Muller with his revue troupe. For reasons of "sound", Muller calls himself "Miller", which, of course, causes more confusion. His daughter, the beautiful Evelyn, is confused with Mabel Miller, who has come to the hotel on a mission for her filthy rich father ... namely, to estimate the worth of the castle.

In the 1800s, a stormy love relationship develops quickly between a young medical student and a woman believing herself to be the daughter of his scientist uncle, the student having never heard of her before their chance encounter and both unaware that she is the result of the scientist's illegal experiments with artificial insemination..

This comedy pokes fun at the military exercises Germans were fond of doing in the lead up to the Great War.

The title alludes to the popular 1925 song I Lost My Heart in Heidelberg composed by Fred Raymond with lyrics by Fritz Löhner-Beda and Ernst Neubach. The film taps into the nostalgic reputation of Old Heidelberg.

An Austrian silent comedy crime film.