With the virus loosed, soldiers cutting off the school, and a makeshift infirmary established to corral those infected, Evelyn decides to fake the illness to make Lucas jealous.
As Garrido heads the excavation of the cave-in, a petty thief emerges among the students, and the bald man from Marcos' dream visits other dreamers as well.
Gullible girls prospect the tunnels for pirate plunder, mistrust abounds, sabotage strikes again, and a smuggled gun only creates new troubles within the infirmary.
With Lucia in need of emergency surgery, Martin hides infected Lucas in the secret loft, Evelyn seeks erotic passion, and the teens seek the scarred bald man of their dreams.
The dig continues; the medicine runs low. Diluting what remains by half seems the best option. As Curro begins groundwork for an insurrection, Evelyn's decision to divorce Lucas leads to a breech.
As the medicine runs out and a fresh murder comes to light, trouble brews in the infirmary, and the teens await the promised reveal of Carolina's killer.
Taking over the infirmary, Curro gives the school one hour to bring medication or else they'll break out; unfortunately, the staff comes to realize they've been misdirected to uncover the wrong cache.
Tensions rise as the medicine reaches its end and senior students plot an escape. Meanwhile, Max' captors hit a snag spawned by the Nazi's own deviousness.
With Fermin's life in immediate danger, the teens hunt for another Nazi mole while envious children, eyeing chocolate, convince Paula she's getting too fat.
Ruben's sudden tirade goads student unrest towards insurrection, turning all but Marcos towards ideas of escape. Meanwhile, Fermin and Rebeca seek to retrieve Max, and Elsa plans for the end.