Sil, the sex-crazed alien life form from the predecessor "Species" is now a clone named Eve (Henstridge). Eve is the acting subject of governmental experiments until a trio of astronauts returns from a trip to Mars and one starts behaving rather strangely. Astronaut Patrick Ross (Lazard) begins to act eerily similar to Sil in that sexual predator sort of way that Henstridge made so endearing in "Species."