Der Lehrer revolves around the teacher Stefan Vollmer (Hendrik Duryn) who teaches German, Science and PE. After 10 years he comes back to be a teacher again. His new school turns out to be very problematic with students hanging around in the halls and not listening to teachers. Vollmer becomes expert for the so-called "G-Kurs" which is the most chaotic class in the school. With new and unconventional methods he finally succeeds to come through to his students and change their attitude against school.