Sequel to Sjunde himlen (1956). Dr. Lovisa Sundelius (Sickan Carlsson) and radio host Willy Lorens (Hasse Ekman) have been happily married for a couple of years, but when Willy becomes a TV host with cutie Suss (Lena Granhagen) by his side, things start to fall apart
Research chemist Barnaby Fulton works on a fountain of youth pill for a chemical company. One of the labs chimps gets loose in the laboratory and mixes chemicals, but then pours the mix into the water cooler. When trying one of his own samples, washed down with water from the cooler, Fulton begins to act just like a twenty-year-old and believes his potion is working. Soon his wife and boss are also behaving like children.