A rocket containing bio-hazardous material to be disposed of by launching into space crashes in a remote wooded area. An army team is sent to recover it. One of the men is infected and mutates into a monster, killing most of the rest of the team. One man escapes with the help of a brother & sister who live in the woods. He then tries to stop his former buddy, while also fighting against another army team sent in to destroy everything. The bio-material was supposed to create a super-soldier, was banned, and the crash of the rocket appears to have been deliberate so the experiment could proceed. But who is behind it all? And will others be infected?

In 1993, the Search for Extra Terrestrial Intelligence Project receives a transmission detailing an alien DNA structure, along with instructions on how to splice it with human DNA. The result is Sil, a sensual but deadly creature who can change from a beautiful woman to an armour-plated killing machine in the blink of an eye.

A scientist, Dr Holander, takes his niece Miranda to Mexico in an attempt to reverse the effects of the alien DNA he used to create her. However the treatment goes horribly wrong, and sets Miranda on a killing spree as she sets out to find a mate.

After she delivers her child in an ambulance, alien Eve is killed by a half-breed. Fortunately, Dr. Abbot scoops up the baby alien and escapes. In time, the baby grows into a gorgeous blonde named Sara and begins her quest to find a worthy mate. But Sara is also savage and leaves a trail of deaths in her wake. This carnage makes chemistry student Dean question whether to help her race or not.

Having just returned from a mission to Mars, Commander Ross isn't exactly himself. He's slowly becoming a terrifying alien entity with one goal -- to procreate with human women! When countless women suffer gruesome deaths after bearing half-alien offspring, scientist Laura Baker and hired assassin Press Lennox use Eve, a more tempered alien clone, to find Ross and his brood. Before long Eve escapes to mate with Ross.