Peter, Paul, and Heinz have been best friends since early childhood; the first two are treated almost like Heinz's own children by his parents, Mr. and Mrs. Liebitz. One day, a terrible accident occurs during a regatta: Heinz falls into the water and drowns. Despite this horrific event, the bond between Mr. and Mrs. Liebitz and Paul and Peter only intensifies. The elder Liebitz owns a musical instrument manufacturing business, and since Heinz will no longer be able to take over the company as originally planned, Franz Liebitz comes up with the idea that Peter and Paul should run the business instead. The two young men receive training in instrument making, but they don't want to become dependent on him and decide to earn their living by repairing instruments and/or as music teachers.
| Actor | Role |
|---|---|
 Paul HenckelsFranz Liebitz | Franz Liebitz |
 Hildegard KnefZwilling ohne Leberfleck | Zwilling ohne Leberfleck |
| MMaria MildeZwilling mit dem Leberfleck | Zwilling mit dem Leberfleck |
 Hansi KnoteckEva Aderholz | Eva Aderholz |
 Albert MatterstockOtto Karnewaldt | Otto Karnewaldt |
| HHellmuth PassargeNot listed | Not listed |
 Wilhelm BendowNot listed | Not listed |
 Elga BrinkElli Liebitz | Elli Liebitz |
| FFanny CottaNot listed | Not listed |
 Erich FiedlerNot listed | Not listed |
| CClemens HasseNot listed | Not listed |
| HHeinz LauschPaul Berkenhoff | Paul Berkenhoff |
| IIngrid LutzNot listed | Not listed |
 Lutz MoikNot listed | Not listed |
 Gustav PüttjerNot listed | Not listed |
| EEdhilt RochellNot listed | Not listed |
 Erna SellmerNot listed | Not listed |
| HHans StiebnerNot listed | Not listed |