The show starts with the tale of Chitose Fujinomiya, a girl who goes from riches to rags and back and remains a snob despite it all. When her wealthy father dies, remaining debts leave Chitose almost broke, and she is kicked out of the affluent Tokai no Gakuen, or City Academy. She is left with nothing in the world but the clothes on her back and one pink goldfish named Gyopi-chan, the only memento she has of her father. Wandering lost, she collapses on the grounds of the poor-but-happy Inaka no Chugakko (Country Jr. High School), where the students are rough if friendly, and farm animals regularly roam the school grounds and even attend class. Recovering, she enters into the school but is repelled by its air of poverty, to which she is unaccustomed. (Source: AnimeNfo)

Nozomu Itoshiki is a high school teacher so pessimistic that even the smallest of misfortunes can send him into a pit of raging despair; some of these "catastrophes" even lead to suicide attempts. Sayonara Zetsubou Sensei is a satirical slice-of-life comedy set in the modern day, covering various aspects of Japanese life and culture through Nozomu and his interactions with his students: Kiri Komori, a recluse who refuses to leave the school; Abiru Kobushi, an enigma who frequently arrives to class with severe and mysterious injuries; the hyper-optimistic Kafuuka Fuura, Nozomu's polar opposite; and several other unusual girls, all of whom are just as eccentric as their teacher. [Written by MAL Rewrite]

More crazy antics abound as Nozomu Itoshiki (a.k.a Zetsubou-sensei), who is the worlds most negative person, tries to teach class 2-F about how life is filled with despair and darkness. A harder task than it first may seem, with his students being far from ordinary themselves, including the likes of the most positive girl he has ever met, his very own stalker, a foreign exchange student with split personalities and a perfectionist acting class president, due to the fact the real class president can't be seen by anyone, among others. (Source: ANN)

Nozomu Itoshiki is still the bizarre teacher of the even stranger Class 2-F. He attempts to teach his students the negative aspects of the world and society, only to have each circumstance thrown at his face whenever he tries. With more students and friends than before, Zetsubo-sensei's life becomes harder and crazier than ever before. (Source: ANN)