Koyomi Araragi is no stranger to the abnormal. During the spring break of his third year in high school, a fateful encounter with vampire Kiss-Shot Acerola-Orion Heart-Under-Blade turns him into a vampire himself. Thrust into the world of oddities, Araragi finds himself catching classmate Hitagi Senjougahara when she falls down the school stairs one day—but something is amiss. After being confronted by the girl in question, Araragi learns that her weight was stolen by a mythical crab. In spite of Senjougahara's blunt threats, he manages to convince her to let him help. In need of a solution to an abnormal problem, the two visit the mysterious Meme Oshino, a wanderer who saved Araragi from his vampirism.

Bakemonogatari is a tale about the monsters that reside within everyone, but just how deep do they dwell in the people Araragi meets?