Season 1

Akira Nokaido is a typical slacker. On his way home from school, he meets a man named Shirogane. Although he has no interest in what Shirogane has to say, the strange man reveals they will meet again.

While fighting off a Kokushi during school hours, Akira and Shirogane join forces yet again to defeat it, only Akira gets hurt in his shoulder and Shirogane is hurt badly from being bitten by the Kokushi. Shirogane then leads Akira to his "Master" at the Bar Still in order for the two to get healed. While they visit the Master, Akira demands more explanation from Shirogane and receives an item that will enable him to be seen by normal humans.

Kengo's sister, Mayu ,bumps into Akira at the Bar Still while he's there with Shirogane and notices Shirogane.

Akira and Kengo have a fight that forms a rift in their friendship. Will they be able to patch things up or will the darkness within Kengo lead to him being possessed? And we learn more about the mysterious stranger with the eye patch who's been pulling the strings from the start, as well as Shirogane.