Bakemonogatari

Bakemonogatari centers on Koyomi Araragi, a third year high school student who is almost human again after briefly becoming a vampire. One day, a classmate named Hitagi Senjōgahara, who never talks to anyone, falls down the stairs into Koyomi's arms. He discovers that Hitagi weighs next to nothing, in defiance of physics. Despite being threatened by her to keep away, Koyomi offers his help, and introduces her to Meme Oshino, a strange middle-aged man living in an abandoned building, who cured him of being a vampire.