The "Betty", a ship full of mercenaries, comes to the "Auriga". It is bringing several kidnapped humans to be used in experiments. The mercenaries meet Ripley. Their youngest member Call (Winona Ryder) recognizes her name and tries to kill Ripley. Call thinks Ripley may be used to create more aliens. Call is too late. The adult aliens have already been created and quickly escape their confinement. Dr. Wren, one of the ship's scientists, tells them that, in an emergency, the "Auriga" will automatically return to Earth. Knowing that this will free the aliens on Earth, Ripley, the mercenaries, Wren, a surviving marine named DiStephano, and a surviving alien host, Purvis, set out to escape on the "Betty" and then destroy the "Auriga".