The director of a radio station, Dag Simpson, went on a business trip, leaving at home his daughter Katie, who was an ordinary awkward teenager. Upon returning home, Dag barely recognizes his daughter Katie in the stunning beauty she has become. The girl has matured! Several young men are vying for Katie's affections. Their attention flatters Katie, but utterly annoys her father. Dag cannot quite accept that his daughter has grown up, and continues to treat her like a little girl. In the end he consults a psychologist who has written an entire book for fathers whose daughters have reached the so-called transitional age, and begins to follow his advice. He will have to see for himself how effective it is.