Newly nominated for Teacher of the Year, Frank Stimpel has invited the press to film a segment about him and the school. What begins as a favorable profile quickly turns into a scandalous report that paints the entire school in the worst possible light. Swift action is needed.

Stimpel refuses to look the other way any longer and is determined to finally free Director Leibrandt from the clutches of alcohol. Unfortunately, this has unforeseen consequences: sober, Leibrandt is a tyrant, and Stimpel has to figure out how to put the genie back in the bottle. Yunus discovers that Sarah is having a secret affair and decides to find a girlfriend himself; his dating mission begins.

It's supposed to be a simple, annual event: class photos. Stimpel is shocked by his students' obsession with beauty, but suddenly he himself is caught up in the pressure to improve. Between botched makeovers and teenage love chaos, Stimpel suddenly finds himself trapped in the beauty saga.

Bestselling parenting guide author Schubert is coming to the school for a reading—and he brings chaos with him. Because he's Annika's father and therefore also Sahra's ex. She has some scores to settle with him, and Stimpel finds himself caught in the middle of a bitter custody battle.

Stimpel wants to expose the girls skipping gym class and develops a top-secret "period diary." But his entries lead him to a completely different suspicion: Kira might be pregnant! He knows he has to handle the matter with utmost discretion—and soon the whole school knows. Yunus, too, has to grapple with the possibility of pregnancy after his latest one-night stand and is completely overwhelmed.

A gigantic graffiti of a giant penis adorns the school: Stimpel sees this as a personal attack and, together with Yunus, sets out to find the culprit. The two discover that the whole thing is much bigger than a ten-meter-long penis on the school facade – the future of the entire school is at stake!

Berlin, Berlin – We're going to Berlin! On the excursion to the capital, Stimpel is primarily concerned about the safety of his charges, because Berlin is also the crime capital. Suddenly, Osman goes missing. While Sahra and Stimpel embark on a nighttime rescue mission into the Berlin nightscape, the students' arguments escalate at the party in the hotel.

Stimpel has finally reached his goal! At the German Teachers' Congress, he hopes to take home the "Teacher of the Year" award. But instead of the expected funding, he's only offered a set of pencil sharpeners. To save his school, Stimpel must overcome his own prejudices and risk everything – going against his German instincts.