"The name's Haru Heiwajima-Orihara, better known as Harry Potter."

Izaya Orihara wakes up in a strange empty area that's completely blank. Shizuo Heiwajima appears and they soon realize they are stuck inside the mind of a child. A child known as Harry Potter, as a matter of fact. The two decide to protect the boy until they can find out why they're in his head, and how to get out. But as the years pass, strange things start to happen to their host, and Izaya and Shizuo must learn how to protect Harry, who is now going by Haru Heiwajima-Orihara because of them, from a magical Hitler wannabe and his magic Nazis, as well as get through a magical school that sounds like it's named after a disease.