Two Hearts in Waltz Time(1930)

Original title: Zwei Herzen im Dreiviertel-Takt

Nicky and Vicky, two librettists who also happen to be brothers, are presently in collaboration with composer Toni. All too aware of Toni's amorous escapades, Nicky and Vicky try to keep the existence of their pretty sister Hedi a secret. Suffering from an acute case of writers' block (he has yet to find an inspiration for his next production), Toni throws a huge party, which is boycotted by his friends and associates so that he'll keep his mind on his work.