Unconscious, unaware, Ripley is the last human survivor of the Nostromo, her shuttle lost in deep space. Meanwhile, the crew aboard the mining ship Marion, faces a catastrophic collision with one of its own dropships and has to contend with the alien infestation on board.

Marooned in a decaying orbit above the planetoid LV-178, the crew struggle to tackle the threat at hand, when an unexpected visitor makes her presence known.