Ripley and Zoe are survivors in a world burned to ashes by the spacefaring Dragoon Swarm. Together with an alien child they rescued, they fight tooth and claw to secure food and water, and evade the toxic fumes that begin to fill the sky.
A hitchhiker named Joel invites the girls to his camp up in the mountains, where he believes he and his compatriots will be safe from the alien Dragoons. Still, tensions are high, as there's already an alien in their midst.