Follow the eccentric Nozomu Itoshiki, known as Zetsubou-sensei, as he endeavors to enlighten class 2-H on the bleakness and despair that saturate life. Tasked with instructing a group of extraordinary students, such as an exceptionally optimistic girl, a devoted stalker, a foreign exchange student with dual identities, and a meticulous stand-in class president (as the genuine one remains invisible to all), Zetsubou-sensei faces a challenging mission filled with unconventional adventures.