Zetsubou-sensei, also known as Nozomu Itoshiki, the individual known for his incessant negativity, embarks on the daunting task of imparting the concept of despair and gloom to Class 2-H. However, this becomes progressively challenging due to the eccentricities of his students, which include an exuberantly positive girl, a determined stalker, an exchange student with multiple personalities, and a perfectionist class president running the show for an absent, invisible president, among other peculiarities.