Bertrand Claverie, a young teacher much loved by his students, commits suicide by throwing his car off a cliff. Bertrand's class is in shock but one student, little Fabien Moreau, a strong-willed 10-year-old, seems to hold the secret of his teacher's death.

Eight-year-old Félix Reynal has just arrived at Louis-Lumière School. He only sees his father, Vlad Mankievic, in secret because he's a thug wanted for murder.

While picking up her daughter, Mylène Delorme knocks over 10-year-old Mehdi on his skateboard. Panicked, Mylène flees, leaving the young boy unconscious. While Mehdi, in a coma, struggles between life and death, the police actively search for the hit-and-run driver.

Eight-year-old mixed race Alison suffers from her parents' disagreements. Her Congolese father Virgil can no longer stand the racism he faces in companies while his French wife, Charlène, is succeeding in her career.

Nine-year-old Muriel Miller is a sickly child who regularly has fainting spells. Her overprotective mother bars her from participating in activities and outings. When Lisa Rivière discovers that Muriel was absent from her checkup, she decides to take a closer look at the child's family. What is this visibly disturbed and omnipresent mother hiding?

Annabelle Cartier, the school's youngest teacher, is an avid online dater. During a date, she rejects an unstable young man, who is now fixated on her. Frightened by his harassment, she calls the police, which doesn't discourage the lovesick man. On the last day of term, he manages to enter Annabelle's classroom and, armed with a revolver, takes the students and their teacher hostage.