Simon Peters (18) has to spend his summer with his Great Aunt Jo. Josephine Barker (70+) has engaged a companion - Susan (24) - because none of her family care about her, only her money.
A brother and sister grow up best friends as USMC officer's children, fall in love, get married, and have a family. All this time they are being taught how to become spies for their country.
Exploits of a masterful swimming coach and his ability to get himself in trouble for letting the 'little-head' do the thinking for him. He does manage to spend most of his life putting together swimming acts and teaching, expecially young women, on how to swim for competition. He also manages shows with syncronized swimming, but there is always the ever present problem of the 'little-head' getting him into trouble.