The movie XIIa is the sequel of the super successful XIa. In XIIa the journey continues. After two years break, Lina is back to school to teach a new class - a new class, new problems. At home, the situation is also not better. Lina is separated with her cheating husband and her dominating mother is constantly bullying her, Lina's son is maltreated by classmates - at times the tension reaches extreme limits and Lina is about to collapse. Fortunately, she finds support in the sports teacher, a former boxer. The school director is also on her side, so are some of the students. Though the problems with the new class, especially with the beautiful and difficult Megan and between Lina and one of her colleague teachers deepen more and more. The prom is getting closer, the situation is about to escalate.