Paediatrician Waldemar Weber is desperate: On his first wedding day, of all days, Egon, his son from his first marriage, suddenly appears at his door. Waldemar has not told his young wife Henny about him until now. It also turns out that Egon is a monkey trainer and has brought his chimpanzees Kiki, Koko and Kaka with him. Waldemar has his hands full explaining Egon's existence...