About 10,000 years ago, peaceful aliens from the planet Antarea set up an outpost on Earth on Atlantis. When Atlantis sank, twenty aliens were left behind, kept alive in large rock-like cocoons at the bottom of the ocean. Now, a group of Antareans have returned to collect them. Disguising themselves as humans, they rent a house with a swimming pool and charge the water with "life force" to give the cocooned Antareans energy to survive the trip home. They charter a boat from a local captain named Jack, who helps them retrieve the cocoons. Jack spies on Kitty, a beautiful woman from the team who chartered his boat, while she undresses in her cabin, and discovers that she is an alien. After the aliens reveal themselves to him and explain what's going on, he decides to help them.