Open-minded, idealistic, funny and self-confident, Sandra is the one who makes the first move with Marcos, the classmate she has a crush on. She, along with Raúl, a new guy who is a bit of a freak, form a group of very different friends who are eager to find their place. Suddenly, his illusions are shattered by a terrible incident: Marcos's father is found murdered and everything points to his son, an apparently normal boy, being responsible.

Nacho is Marcos' older brother, with whom he has a complicated relationship. Studious and responsible, he is unable to rebel against the oppressive environment that exists at home. But deep down he also wants to fly away. For now, his priority is to go to university, while he continues to abide by the dictates of his father. The death of his mother in a traffic accident increases the rivalry between Nacho and Marcos, since both blame each other for the tragedy.

Raúl has just arrived at the institute. Overprotected by his mother, he tries to hatch and find his place. He seems like the typical geek, but Sandra and Marcos see in him an enthusiastic and fun boy, with peculiar musical tastes. He soon falls in love with Sandra, but knows that she likes Marcos. Raúl is also attracted to him and doesn't understand why the three of them can't love each other. He will suffer a severe blow with the arrest of Marcos for the murder of his father.

Marcos is accused of the death of his father, beaten to death with the typewriter with which he forced him to do his homework. He is a boy with no apparent problems, almost a leader, and nobody can explain what happened. Only Álvaro, his Literature teacher, will help him to accept himself and start on the road to improvement. Days before the terrible event, Marcos enjoys with his friends, Sandra and Raúl, the best moments of his life.