The astronaut son of a senator is infected by an extraterrestrial organism during a mission to Mars and causes the deaths of many women upon his return. To stop him, the scientists who created the human-extraterrestrial hybrid Sil in the original Species try using a more docile clone of hers, Eve. The film is a sequel to Species (1995) and the second installment in the Species series.

References:
https://en.wikipedia.org/wiki/Species_II