Le jour où tu ris, tu perds

It's back to school time, and Dorian, a voluntary repeater, is back with his friends, while Charlie, a new pupil, tries to integrate with a sense of humor, but clashes with Dorian.

Mathis is mortified to be accompanied by his mother, who insists on accompanying him to the gate. Clovis, a new pupil, is looking to make friends but is shocked to discover that his big sister, Anaïs, is not as well-liked as he thought. For her part, Dina

The students discover that the school's European flag has disappeared, sparking a debate about its importance and leading to the idea of creating a new flag, but the project descends into chaos when everyone decides to create their own “country”.

Dina, shocked by a revelation about Victor Hugo, leads her friends on a crusade against works deemed problematic, culminating in a radical book-destruction project.

Florence, Lilou's mother and parent representative, arrives at the school with an alarming report on the students' lack of attention, while Stéphane and Marc improvise a teaching method combining sport and history to prove its effectiveness.

Albert is annoyed by Clovis, who clings to him thinking they're meant to be friends because he thinks he's HPI. For his part, Bilal, offended by being made fun of for his cheap T-shirt, swaps with Hippo to look more stylish, but the deal turns sour.

Mathis panics after discovering that the bees in the hive have disappeared, fearing Raph's reaction.

Dorian tries to adapt to English culture by eating beans on toast and drinking tea, while Kayla has to juggle her basketball responsibilities with a stand-up routine.

The students at Truffaut middle school are faced with cleanliness problems and personal tensions, especially between Kayla and Hippo, due to rumors and secrets.

Bilal offers to buy new sweets, but also allows anyone who buys them to become a retailer and sponsor of future customers. Hippo is interested and takes the plunge, but disgruntled customers are quick to come forward (pyramid scheme).

Inspired by the lyrics of his favorite song, Charlie decides to live in “One Life” mode. Clovis prefers to work hard so as to have a good life later on.

At the entrance, the students bicker and joke about their feelings and their pubescent bodies. Dina has started her period and is looking for a sanitary pad. Mrs Lavigne gives important information about tampons.

It's Halloween at Truffaut. Dorian and Hippo make it clear that anyone can dress as he or she wishes, regardless of gender.

On their school trip to Verdun, the girls compete for the attention of the handsome local guide, creating tension and jealousy. For his part, Mathis confides his fears to Raph: he has never been separated from his parents.

With some students still uninterested in the war, Marc has decided to pull out all the stops, thanks in particular to a historical re-enactment association. The trip will raise awareness.