Sayonara, Zetsubou-Sensei revolves around a very pessimistic high school teacher named Nozomu Itoshiki who, at the very beginning of the series, tries to hang himself on a sakura tree. Despite this effort of self-destruction, he is saved by an extremely optimistic girl known only as Kafuka Fuura (though in her effort to save his life, she almost kills him). She explains to him that it is simply unimaginable that he would hang himself on such a nice day, especially in front of such beautiful trees.