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.

A sensitive girl is sent to an all-girls boarding school and develops a romantic attachment to one of her teachers.

A German soldier home on leave falls in love with a girl, then returns to World War II.

The two main people in the story are Anna, a young girl, who is thought of having the ability to heal people mysteriously. Elisabeth is a young - middle aged aristocratic woman, that is disabled and puts all her hopes in meeting Anna and having her disability heal by her. A strange ambivalent relationship develops between the two women.

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.

Based on a book by Vicki Baum, all of the action takes place in one day in a luxury hotel in Berlin. Grusinkaya is a ballerina staying at the hotel, other guests include Baron von Gaigern a sophisticated thief, Otto Klingelein a dying man, Preysing a businessman, and a stenographer. Events intertwine the lives of these strangers, bringing them together for some dramatic moments.

In a deeply cloistered convent, nun Dorothea Wieck raises a foundling to be Evelyn Venable. But at 17, what if, guided by a kindly doctor, she sees the world and finds love?

Miss Madeline Fane is a famous California screen star who has been devoted to her baby son Michael since her husband's death the previous year. One morning she awakens to find Michael has been kidnapped. After a day, she calls in the police, who instantly begin an all-out search.

Thomas Holinka has returned home from war and captivity. In the absence of a suitable home, he finds himself in what seems to be an abandoned monastery. When the nuns return, a conflict is inevitable because Holinka is addicted to alcohol and gambling .

In 1920, an unknown 24-year-old woman was fished out of Berlin's Landwehr kanal after a suicide attempt. Since she has no papers and no answers to any questions, they soon assign them to the insane asylum Dallendorf. A co-patient believes she recognizes the Czar's daughter Anastasia Romanowa - who apparently was the only one who survived the murder of the tsar's family in 1918.