Bakemonogatari Vol. 9 [Regular Edition]

Koyomi Araragi is a third-year high school student who survives a vampire attack and is left with residual side effects, including superhuman healing and enhanced vision. All he wants is to return to being a normal high school student, but one day he makes a strange discovery. When he catches classmate Hitagi Senjougahara after she falls down the stairs, he realizes that she weighs a lot less than she should. In fact, she weighs nothing at all! Intrigued by such a bizarre case, he dives back into the world of the supernatural in order to help find the cause and cure Hitagi of her affliction.
Notice: This book is written in Japanese.