Ripley, who awakens on Earth only to discover that she has been hibernating in space so long that everyone she knows is dead.
Then she is talked into traveling (along with a squad of Marines) to a planet under assault by the same aliens that nearly killed her.
Once she gets there, she finds a lost little girl who triggers her maternal instincts--and she discovers that the company has once again double-crossed her, in hopes of capturing one of the aliens to study as a military weapon.