First part: The central figure of Class 406 is Francisco Romero, a high school teacher, who has just arrived at the Mexico City. In the daily coexistence with his new students he will discover that it is not sufficient to just teach his subject; that to gain their respect and to be a positive influence in their lives, he has to be more than authority, he has to be their friend. Francisco will become a witness to the heartbreaking episodes in the life of these young people: domestic violence, pregnancy, addictions, poverty, prostitution and crime. He will realize that he cannot remain a simple spectator; in addition to being a teacher, his heart impels him to assume the role of advisor, doctor, psychologist, defender and even detective.
Second part: Francisco is caught in a love triangle. He is caught between Angela and Ana Maria. He realizes that he loves Angela and they become a couple and Ana Maria stays with Juan Esteban, the school counselor. But Francisco and Angela have a big problem. Juan David is Angela's son. He will not allow his mom to marry Francisco and will do anything to separate them. After a while he realizes that Francisco is his mom's true love. At the end of this part Francisco gets married and leaves the school leaving his Clase 406 behind. Magdalena (Iran Castillo) also left at the end of this part.
Third Part: Santiago, a new teacher, arrives at the school. He is really mysterious and hides a big secret. His secret is that he accidentally killed his fiancée. Jessica (Anahi) is obsessed with Santiago and will do anything to find him. It was her fault he killed his fiancée. When she finds him she finds out that he is now in love with Nadia. Jessica will do anything to separate them. While trying to separate them Jessica falls in love with Kike, a young boy from "La Banda 406". She later forgets her obsession for Santiago and asks him and Nadia for forgiveness. At the end of this part Santiago and Nadia get married and Jessica gets in a mental institution.
Final Part: Time passes and the Clase 406 are in college. Gabriela is in the top college and is on her way to law school. Marcela is in a photography school. Daniela is a married women and stays home. Tatiana is in college. Juan David is in the music industry using Caballo's voice. Freddy has broken up with his boyfriend and is looking for love. And as for Kike and Jessica they're happy in their new home. But everyone's life changes with the arrival of Samsara who wants revenge on them because she believes it was their fault the old villain Leonardo died. Her revenge will go more towards Fercho and Tatiana and she will try to separate the whole group and make them all enemies. Samsara dies in a car accident in an attempt to kill some members of the Clase 406. On Kike and Jessica's wedding day they decide not to get married. The priest asks if anyone else wants to get married. Gabriela and El Gato decide to take their place. And the Clase 406 make a promise to always stay friends and to always be the Clase 406.moreless