Follows Álvaro, a 17-year-old from a wealthy family, whose life takes a downward turn after an accident lands him in a juvenile detention centre. It portrays his experiences and struggles within the correctional facility.
Two new inmates, Carlos and Álvaro, arrive at the Juvenile Detention Center, CIMI, in Alicante. Through their eyes, we're introduced to the complex dynamics of the institution, such as the power structures, the daily routines, and the web of relationships that define life inside. The key players include the administrators who run the center, the guards who enforce the rules, and the other young offenders who make up this tightly controlled world.
Carlos remains in the crosshairs of Los Pajaritos, who refuse to let up, making his days inside the CIMI increasingly tense and dangerous. We also discover that Saray is intellectually sharp and emotionally aware, yet she chooses to remain within the confines of the center, seeing it as a safer alternative to the instability of life outside. In the end, the verdicts come down. Both Carlos and Álvaro are found guilty and must face the reality of serving out their full sentences.
Los Pajaritos start circling around Álvaro, intrigued now that word's gotten out he's taken a life. His reputation is suddenly earning him a dangerous kind of respect. Saray, too, begins to draw closer, sensing something deeper beneath his guarded demeanor. Meanwhile, Carlos is hit with news that turns his world upside down. He's going to be a father.
Álvaro starts working for Los Pajaritos and loses the support of Carlos, who receives a brutal ultimatum. Kill Mario or they will kill Nina. Marina confesses to Saray that she came to CIMI for abandoning her newborn baby.
Carlos is under intense pressure from Los Pajaritos to kill Mario, but he simply can't bring himself to do it. Meanwhile, during his weekend release, Los Pajaritos inform Álvaro of their plan to plant drugs in his father's car trunk, a move that pushes Álvaro to turn against them.
Upon returning to the CIMI, Saray clashes with Álvaro, and, under Violeta's influence, Marina abandons her. In an effort to shield Álvaro, Carlos successfully pits Ray against Álex, while Los Pajaritos relentlessly tighten the noose, pressuring him to put an end to Mario once and for all.
Carlos reaches his breaking point and manages to flee the CIMI with Nina. Álex attempts suicide but leaves behind a note beforehand. Meanwhile, Ray catches on to the fact that Álvaro and Carlos have betrayed him and is determined to track them down.
Carlos is sent back to the CIMI, landing in solitary confinement alongside Álvaro. Meanwhile, Ray and Los Pajaritos orchestrate a riot in the auditorium. But it's just an elaborate distraction to conceal their real objective of assassinating Álvaro.
