Frank Stimpel has to prove himself at his new school. In his first week, he loses the class's respect, and the police show up. Principal Aminata would love to kick him out again, but she needs the German teacher.

Stimpel wants to curb the aggression among the students. He makes several attempts until it becomes clear who the real problem is: the passive-aggressive Alman teacher himself!

To increase his chances of becoming a civil servant, Stimpel establishes a robotics company. But instead of action, the German prefers theory. His colleague Yunus counters this and establishes a combat robot company, which challenges Stimpel to a major showdown.

Stimpel becomes a guidance counselor and wants to prove himself in his new role to his boss, Aminata. Just when his student Leyla is in an emergency situation, the task becomes overwhelming.

Stimpel learns about an online ranking that rates the school's teachers based on their coolness. To earn the class's respect, he desperately tries to loosen up. To do so, the German has to step out of his comfort zone and resort to unusual means.

To raise money for the class trip, Stimpel initiates a school flea market—a hands-on way to learn economics. The fierce competition between him and Sahra, and the battle of supply and demand, leads to a "nasty situation."

Despite German customs, a new teacher captivates everyone with his open pedagogy and relaxed manner, causing Stimpel to doubt himself. When the new teacher then starts flirting with his colleague Sahra, Frank realizes: There can only be one German!

Stimpel's attempts to improve security at the school fail due to class resistance. The Stimpel Security organization, or StiSi for short, he founded, aims to change this by any means necessary. But the German's plans begin to divide the entire school.

Stimpel, Sahra, and the entire class are going on a school trip to the forest – except for Stimpel, everyone finds it completely boring. Alman wants to change that and provides a little thrill. But the forest has its own rules.

Stimpel's big day is approaching: the teacher's exam! His class's drug problem comes at a very unfortunate time. To demonstrate the potential consequences to the young people, he conducts a self-test with fatal consequences.