Much to his pleasure, young pianist Hans Peters has just been offered his first engagement, which will lead him to the well-known Frank Witte dance band. A jump of joy on the stairs, however, has bad consequences: Hans slips and twists his arm, especially, so the next obligation probably won't work. In either case, the doctor orders you to rest for at least two weeks. Tonight, however, he should start the tour with the Witte combo. When Hans doesn't know what to do next, his clever sister makes an unusual suggestion: why shouldn't she dress up as Hans Peters and go on tour instead of him? Said and done. At first, Witte is surprised by the too youthful appearance of the young piano virtuoso, but then he does not give him a thought.