Natsume's Book of Friends, Vol. 6

Takashi Natsume has always been aware of the supernatural world, but after he inherits a magical book from his grandmother, the supernatural world is aware of him!
Takashi Natsume can see the spirits and demons that hide from the rest of humanity. He has always been set apart from other people because of his gift, drifting from relative to relative, never fitting in. Now he's a troubled high school student who has come to live in the small town where his grandmother grew up. And there he discovers that he has inherited more than just the Sight from the mysterious Reiko.
Takashi rescues a young boy named Kai from an abandoned house, where he had been locked in a box. But this isn't just a case of bullying gone too far. Kai has been complaining about being chased by ghosts. Does he see yokai too, or is there something darker going on?