Zwei Herzen im Dreiviertel-Takt (1930)

Toni Hofer and brothers Vicki and Nicki Mahler are working on a new operetta. Toni's reputation with women equals his fame as composer, so they keep their sister Hedi away from him. Wanting to know him, she calls at his house in the middle of the night not revealing her identity, helps him write the main waltz theme and disappears, leaving him incapable of remembering his greatest melody. Music by Robert Stolz.