The details of Ari's attack are revealed but the Las Encinas students prove yet again there is always more than meets the eye.
Guzmán and Ander are seen prematurely saying goodbye at Ander's house; Ander has decided to leave Las Encinas halfway through the school year. Later, Rebe decides to help Mencía by telling Ari about the situation she is in with Armando. Rebe understands that revealing the truth means that she likely has no future with Mencía, but she feels she has no choice.
Prince Phillipe goes to talk to Cayetana in the janitor’s room. She asks him to leave, but he persists and apologizes for his misconduct the previous night. When the conversation moves into the hallway, Benjamín watches them through the CCTV cameras. Phillipe claims that Cayetana was giving “mixed signals” at the party; this comment disgusts her and she walks off. Later, Ari confronts Mencía over Rebe’s claims. Mencía denies everything, but then tearfully says she will never speak to Ari again if she tells Benjamín.
Learning that Ander is leaving Las Encinas, Omar asks Ander to give their relationship a second chance. Ander asks Omar if he wonders where he would be now had he gone to New York with Malick. Although initially hesitant, Ander decides that he will stay, and the two passionately kiss. An angry Patrick watches in the background.
The Royal Highness meets with Cayetana in Benjamín's office in an effort to get Cayetana to keep quiet about Prince Phillipe's sexual misconduct. She tells Cayetana that Phillipe has chosen her over anyone else, and reminds her of the financial struggles she would no longer have to face if she accepts Prince Phillipe. The Royal Highness further adds that it is a man’s "biological impulses" that cause them to behave in the way they do. Cayetana is tearful and appears extremely anxious.
Edging closer to Ari’s attack, the lavish New Year’s party begins. The Royal Highness is eager for Cayetana to approve of Prince Phillipe, but Cayetana ultimately refuses, saying “Your son’s vigour is not a question of biology, your highness, but of upbringing.” The Royal Highness and Phillipe are appalled. Phillipe confronts his mother and scolds her for raising him to be a fool, reflecting Cayetana’s words. The Royal Highness responds that if Philippe wants to be an adult, he needs to accept the consequences of his own choices.
Back together with Omar, a happier Ander convinces Guzmán to talk to Ari. However, before he has the chance to, Samuel asks Ari for a minute of her time: he begs Ari to leave him alone and to get back together with Guzmán. However, spotting the exchange from a distance only brings further anger for Guzmán. Inside the club, Patrick angrily watches Ander and Omar dance together. Finally giving up on them, Patrick hooks up with a random male student at the party.
Omar learns that Ander’s reason for wanting to leave Las Encinas is to travel the world, and he tells Ander to follow through with his dreams. He insists he can wait for Ander to return, and the two share a kiss. Later, Phillipe is shown sending a voice message to Elodie, a girl he once abused. Philippe apologizes and admits to abusing her, telling her to do with this confession as she deems fit.
Following a slightly tense conversation with Ari, Rebe spots Armando getting physical with Mencía on the dock of the lake. Rushing over to intervene, Rebe attacks Armando and escapes with Mencía. From afar, an intoxicated Ari witnesses the situation, confirming that Rebe’s claims about Armando are true. Ari confronts Armando alone and threatens that she will tell her father everything. Ari phones her father, but before she has the chance to say anything, Armando hits her. Amando continues to beat her as she attempts to crawl to her phone. At the same time, Guzmán and Samuel get into a vicious brawl in the club. In a fit of rage, Guzmán beats Samuel to a pulp, only to spot a message from Ari on Samuel’s phone asking him to meet her by the lake so she can explain everything. All of this simultaneously happens as the clock strikes midnight and the new year arrives.
Stumbling out of the club, Guzmán finds a barely conscious Ari on the dock of the lake. She weakly asks him to go after Armando. Ari attempts to stand up, but when she reaches for for her phone, she collapses into the lake. Meanwhile, Guzmán hunts down Armando, who attacks him. They get into a brawl in a storage room, but before Armando can escape, Guzmán grabs a flare gun and shoots him dead. Guzmán is traumatized upon realizing what he has done. He wearily returns to the dock to search for Ari, but unaware that she is floating unconscious in the water, he searches elsewhere for her.
Guzmán stumbles into the club and frantically asks Samuel and Rebe if they have seen Ari. He breaks down and tells them what has happened. They all agree to call the police but make an arrangement not to inform of all the details. Rebe assures Guzmán that he will remain innocent. In critical condition, Ari is whisked to the hospital in an ambulance, and after the events previously shown in flash-forwards, she is shown recovering and alive.
In the hospital, with Ari fully conscious, Guzmán comforts her but says he knows she loves Samuel and not him. He also lies about Armando’s death, telling her that he ran away. Guzmán bids Ari farewell as she tearfully begs him not to leave.
Some time later, Guzmán and Ander leave Las Encinas to travel the world together. They tearfully bid farewell to Omar, Cayetana, Rebe, and Samuel before driving away. Feeling awful over how she brought Armando into their lives, Mencía asks Ari to be by her side when she tells Benjamín about her relationship with Armando. As the truth is revealed to Benjamín, he is seen in a fit of rage, destroying items in his house. Finally, it is revealed that Guzmán, Rebe, and Samuel all threw Armando’s dead body into the lake after the murder.