While fishing at the beach, Shaggy Rogers snags and pulls ashore a giant block of ice containing a frozen caveman. Velma Dinkley recognizes it as a two million-year-old caveman discovered in the Arctic and washed over the side of research vessel during a storm. The kids take it to Oceanland and leave it with two scientists, Professor Wayne and Professor Ingstrom. After they leave, someone turns a space heater onto the caveman; Ingstrom leaves for the dockside while Wayne remains behind to work on some research notes. At the Malt Shop, Shaggy remembers that he left his fishing tackle at Oceanland, and the gang returns to pick it up. They find the doors ripped off its hinges, Wayne's torn parka, and the caveman thawed out and missing. The phone is broken, so the kids decide to investigate. T