Fearing that his recently-acquired step-mother, Ann Dennis, is competing with him for his father’s affections, and saddened by the death of his dog, young Danny Mitchell, in the first film of the long-running “Rusty” series, seeks consolation in the companionship of a ferocious, Nazi-trained police dog, Rusty, brought to the U.S. by a returning WWII-veteran. The step-mother, with tender understanding, eventually wins Danny over while Danny pacifies his new dog.
After a shipwreck takes the lives of both his mother and father, Robby is saved from drowning by the young island native Friday. The Caucasian castaway and the young native become close friends and live together in a peaceful, idyllic co-existence that is underscored by their oblivion to racial stereotypes and prejudice. When a passerby novelist comes to the island and recognizes the wealthy boy, he takes both boys with him back to civilization. He promises they’ll remain together, but the viewer rightfully doubts his word, because when they arrive, the boys are separated due to society’s racial bigotry.
The siblings Kate and Ben and their friend Spider are fascinated by an old mansion called ‘Castle House’ on the far side of the river next to their village. The mansion has been uninhabited for 15 years, but when they explore the premises they notice a mysterious coming and going. When the old owner, the friendly Mrs. Markham suddenly appears – and as suddenly disappears again – things become even more mysterious.