Las Cumbres Boarding School is an impenetrable fortress built on the edge of a cliff where students are subjected to strict discipline and it seems impossible to escape. However, two of them manage to run into the woods one night, but things take a turn for the worse because surviving outside the school is even more dangerous than inside and the woods are much more terrifying.

Adéle tells Alba's secrets, which surprise everyone. Darío takes his daughter Inés home, near the school, where she has very strange visions. An unexpected postcard from Manuel assuring that he's all right discredits Amaia's story about his disappearance. León sneaks into Darío and Inés' home, the students organize a secret party and Elías and Elvira grow closer.