В далеком будущем возвращающийся на Землю грузовой космический корабль перехватывает исходящий с неизвестной планеты неопознанный сигнал. Экипаж принимает решение совершить посадку и разобраться, в чем дело. Оказавшись на планете, астронавты повсюду обнаруживают неопознанные предметы, по виду напоминающие гигантские коконы…

Two hundred years after Lt. Ripley died, a group of scientists clone her, hoping to breed the ultimate weapon. But the new Ripley is full of surprises … as are the new aliens. Ripley must team with a band of smugglers to keep the creatures from reaching Earth.

After escaping with Newt and Hicks from the alien planet, Ripley crash lands on Fiorina 161, a prison planet and host to a correctional facility. Unfortunately, although Newt and Hicks do not survive the crash, a more unwelcome visitor does. The prison does not allow weapons of any kind, and with aid being a long time away, the prisoners must simply survive in any way they can.

When Ripley's lifepod is found by a salvage crew over 50 years later, she finds that terra-formers are on the very planet they found the alien species. When the company sends a family of colonists out to investigate her story—all contact is lost with the planet and colonists. They enlist Ripley and the colonial marines to return and search for answers.