In 1974 scientists used the world's largest radio telescope to send messages into outer space. Twenty years later they receive a message giving instructions on how to mix human and alien DNA to form 'Sil', a new species. The scientists create 'Sil' - in the shape of a beautiful young woman (Natasha Henstridge) - who escapes from the observation facility. She must be stopped before she mates with a human male and creates a new species which could overwhelm mankind. A team is assembled to destroy 'Sil', led by scientist Xavier Fitch (Ben Kingsley) and containing an assassin (Michael Madsen), a biologist (Marg Helgenberger), an anthropologist (Alfred Molina) and an empath (Forest Whitaker).