Shingo Kusaka, the illegitimate brother of KUSAKA Group chairman Shunichiro Kusaka, is framed and sentenced to death by his own bloodline. Surviving the brink of death, Shingo erases his past and is reborn as a professional assassin—only to find himself hunted by an unknown enemy.

Five-dollar hitman Mayo and KUSAKA Group chairman Shunichiro Kusaka are half-brothers living in completely different worlds. When the underworld Matsuri Clan plots to seize control of the KUSAKA Group, the long-feuding brothers find themselves facing a common enemy.