The Monogatari series revolves around Koyomi Araragi, a third-year high school student who has almost restored his humanity after briefly becoming a vampire during spring break. One day, a classmate of his, the reclusive Hitagi Senjōgahara, falls down a flight of stairs at school into Koyomi's arms. To his surprise, he discovers that Hitagi weighs almost nothing, in defiance of physics. Despite being threatened to keep away, Koyomi offers his help and introduces her to Meme Oshino, a strange middle-aged man living in an abandoned cram school who helped reverse his vampirism. Once Koyomi helps solve Hitagi's problem, she decides to become his girlfriend.