While Pippi is sailing with her sea captain father, she is suddenly washed overboard and lost in a fierce storm. Pippi eventually drifts ashore to a small coastal town where she sets up house in an ancient vacated mansion. There, with her horse and monkey, Pippi begins a new life without any adult supervision

Captain Longstocking docks in the village to pick up Pippi and take her with him to the South Seas. Annika and Tommy are given permission to go along and they all set sail for adventure on the high seas. Unbeknownst to the Captain and crew, Thunder Karlson and Bloom are castaways yet again in search of their fortunes. Unfortunately, they get very seasick and the fortune is not as easy to access as they had hoped.