Yanka, a circus performer, gets pregnant when a mysterious creature slithers into her body while she sleeps. As the monster grows inside her, it learns to communicate with her telepathically. To fully develop, the monster urges the unwilling woman to feed on the blood of human men, threatening to hurt her from within if she doesn’t comply. Initially, she loathes her offspring, but as time passes, she becomes protective over the creature and does everything she can to help it accomplish its mission to return to the place from whence it came.