S.E.T.I - Search for ExtraTerrestrial Intelligence - sends a message to outer space to whatever intelligent life form out there might be listening. Around twenty years later, S.E.T.I receives a message back from an unknown life source, giving S.E.T.I their version of the DNA structure and instructions on how to mix that life source's DNA with the DNA of the life on earth. The science team successfully creates a creature, a hybrid with both forms of DNA, in which they codename Sil(Natasha Henstridge). Due to some mistakes, however, the experiment had to be terminated. As they are gassing Sil with Cyanide poisoning while she helplessly panics inside a heptagonal glass casing, Sil who was then a young teenager breaks out of the lab and successfully manages to escape. Sil causes trouble, murdering innocent people, and then she sits in a cocoon on a train and erupts a fully grown woman. Sil might be incredibly gorgeous and very intelligent, but she proves to be extremely deadly. She is on a mission to try and mate with a human male. Government agent Xavier Fitch(Ben Kingsley) assembles a team of scientists and mercenaries to locate and destroy Sil before she manages to find a mate and breed.