Pediatrician Waldemar Weber is at his wits' end. Of all days, his adopted son Egon—from his first marriage, whom Waldemar has always kept a secret from his young wife Henny—has announced he’s coming to visit on their first wedding anniversary. Waldemar must stop Egon at all costs. When Egon finally shows up at the door, he turns out to be a monkey trainer.
| Actor | Role |
|---|---|
 Heinz ErhardtEgon Kummer | Egon Kummer |
 Corny CollinsHenny Weber | Henny Weber |
 Adrian HovenDr. Kurt Wehling | Dr. Kurt Wehling |
 Grethe WeiserMathilde Nathusius | Mathilde Nathusius |
 Gunther PhilippDr. Waldemar Weber | Dr. Waldemar Weber |
 Ruth StephanAnna | Anna |
 Hans RichterBehnke | Behnke |
 Rudolf VogelTheodor Nathusius | Theodor Nathusius |
| CCarmela KünzelHelga Lüders | Helga Lüders |
| FFriedel HenschSängerin | Sängerin |
| PPeter SteffenSänger | Sänger |