The kids are in Norway to find out what happened to Professor Busby, the archaeologist, who was studying the old viking ruins. It seems that some vikings have come back and kidnapped him, but before too long, Daphne and Scrappy are kidnapped too and Shaggy and Scooby have to save them. / The kids head to the island of Scareruba, to see Prince Ruba, and take pictures of the surfing festival and legendary surfer Cowabunga Carlyle. But while there, they hear of the "Lost treasure of Scareruba" and the Great White Shark and Seaweed Monster who are protecting it.