In a flashback, Valle and her friends get into trouble when they activate an old train, leading the authorities to move them to an upper sector. In the present, the government decides to interrupt the Sanctuary project and extract the babies; Valle tries to save Pilar and Rocio, but Rocio is disconnected while Valle and Pilar manage to escape with the unexpected help of Victor.

On their risky journey to the bunker, Valle and Pilar traverse a hostile wasteland, facing environmental and assaulting dangers. Once in the bunker, Valle meets up with Silvia and Bosco, who are experimenting with artificial wombs on women. Bosco wants to remove Pilar's uterus to obtain key data, but Valle doubts his intentions.