One day, in the city of Night Town, a boy named Hajiki Sanada is assigned to make a special delivery for a very mysterious client. Hajiki accidentally opens the package, only to find a mysterious black cube known as a GAD! The next day he meets a girl named Arashi, and the thieving Jack Gang. The Jack Gang tries to steal the GAD, but when Hajiki bonds with it, the GAD reacts...
