HE THOUGHT ONLY HE COULD SEE THEM...Rather than hanging out with his peers, Tobi Otogiri spends most of his time chatting in secret with his pal Baku, a mysterious backpack he received the day he last saw his older brother. Or, at least, Tobi doesn't think anyone is listening until a girl in his class named Ryuuko suddenly asks him about Baku. Not only can she hear his backpack's voice, but she can see the weird entities attached to the people around them, just like Tobi. Could those strange things be behind the recent series of odd occurrences at their school?