During a landing on Mars, astronauts collect soil samples that infect them with an alien substance when they return to Earth. The returned astronauts encounter accelerated pregnancies and give birth to human-alien hybrids. Meanwhile, scientists create a clone of Syl named Eve to study alien life. Ross, the astronaut commander, goes through a series of strange events and his body is subjected to alien instincts. The scientists activate Eve's telepathic link with Ross and direct her to track him. Eventually, a team of astronauts and scientists battle Ross and his hybrid descendants in an attempt to stop the spread of alien hybrids. The battle ends with Ross' death and Eve's rescue, however she turns out to be pregnant and her belly quickly swells.
