A young European boy living in San Francisco is reluctant to marry his long-term girlfriend because he wants to travel around the world first. His wealthy uncle agrees to send him on a global expedition aboard his ship, but en route the boy and his travelling companion are shipwrecked on a remote island, populated by countless prehistoric creatures as well as gold-hunting bandits.

After a meteor-like object lands in the woods, poachers unearth a cave filled with alien eggs. As they attempt to destroy the eggs, one of them is killed by an unseen creature, leaving one egg intact. A young boy named Tommy finds the remaining egg and brings it home to hatch. As more murders occur around town, Tommy learns that his new pet alien, who he names Trumpy, possesses telekinetic powers.