Serial optimist Kafuka is surprised when she bumps into her new school teacher, Nozumu Itoshiki, hanging by the neck from the bough of a lovely blossoming cherry tree. As he'd been dangling there quite voluntarily, he's only more depressed when she "helps" him down (nearly killing him in the process). Her cheerful declaration that he was just trying to make himself taller only adds to his frustration. Resigned to finding an opportunity to kill himself later, he follows her to class and begins to meet the rest of his misfit students. One's a love-obsessed stalker, another's a refugee, another can only communicate via rude text messages. Split personalities, OCD, and even the dreaded curse of ordinariness--everybody has issues. So their suicidal downer of a new teacher fits right in.
Such a weird little series, this. Brimming with pop culture references (thank you, end notes!) and stupidly funny graveyard humor, it sports simplified, highly stylized line art with lots of solid black-white contrast, a minimum of screentone, and some nice little details (I love sensei's kimonos). Making a play on his written name, the kids start referring to him as Zetsubou-sensei (Mr. Despair). And then he turns a questionnaire about their future aspirations into one about their future failures. And it's all downhill from there. :)