Species 2 is the sequel to Species and one of four of the Species series. Between two and three years after the movie Species takes place, an American mission is conducted on Mars. They collect soil samples which they take back to the ship. During the return flight, the soil samples thaw, releasing the DNA into the air. After they return from the mission, three of the astronauts are quarantined to keep them from having sex for ten days. One of those astronauts decides to sleep with two women against the advice of the medical team. The women that he is sleeping with notice that he is not completely human. Both women are impregnated and go through a rapid pregnancy. The alien hybrids are born at the cost of their mothers' lives. The astronaut's name is Patrick.
He returns to his fiancee and has sexual intercourse with her. She undergoes the same rapid pregnancy while he sleeps. He wakes to her body, lifeless and mutilated. Horrified by what he has done to the love of his life, Patrick shoots himself in the head which kills the human part of him. The alien Patrick resurrects and continues to find women to mate with. He finds plenty of women and when they die, he buries them next to his shed. Patrick helps his children to cocoon. This process will enable them to transform into adults which will seek out more humans to mate with. Patrick plans on continuing to mate with humans as long as it takes for him and his children to completely wipe out the human race.
The government finds out about the impending doom and activates Eve's alien DNA. Eve is a clone of Sil, the alien from the first movie. Eve locates Patrick but in doing so alerts him to her existence. He gives himself up to attempt to mate with her. He escapes and Eve breaks out to find him.