When small-time crook Eddy gets caught fleeing a club raid, he's offered a choice: serve jail time or go undercover as a math teacher in a high school.

A tense safety drill and Eddy's late-night meddling send the school into chaos, putting him at the center of suspicion - and closer to Tiphaine.

On a class trip to Normandy, Eddy clumsily attempts to collect DNA samples for Lucie, and a botched attempt to impress Tiphaine sparks controversy.

While a blockade at the school brings mass media attention, Eddy attempts to uncover a mole among the teachers, leading to a politically charged protest.

Professor Fish goes viral across France as Lucie attempts to strike a deal with Sagirov's contact and Eddy makes a stand on local television.

Someone from the past sheds new light and fresh doubts on the case, while Eddy sets up a parent‑teacher meeting so Lucie can hunt for clues.

After a love letter softens Tiphaine's heart, a reckless lie causes accusations to fly and Lucie pushes Eddy beyond his limits to keep the mission alive.

Snipers surround the school as the students settle into the baccalaureate. As panic mounts, Eddy goes rogue to protect a student - at his own peril.