A legendary hitman trained to become the world's best assassin is asked to lay low for a year by the head of his crime family.

Akira is the legendary killer known as the Fable. Following the order of his boss and due to being overworked, he lives peacefully with his partner, Yoko, as ordinary siblings. Akira still works part-time at design company Octopus with CEO Takoda and employee Misaki. CEO Takoda and Misaki are unaware of Akira's background as an assassin. Meanwhile, Utsubo is a representative for an NPO. But, Utsubo works with contract killer Suzuki to set people up for extortion purposes. They target someone at design company Octopus.

The Fable is a legendary yakuza hitman equal to none—but his boss orders him and his sultry associate to lay low and learn how to live a "normal life" in Osaka.