Yoshino, granddaughter of the boss of Osaka's largest yakuza clan, was raised in the heart of the underworld. An education which put lead in her head, but which did not prevent her from leading a peaceful life. Until the day her grandfather decides to get her engaged to the very pleasant Kirishima, grandson of a powerful rival Tokyo clan with a view to uniting the two families. Embroiled in this arranged engagement, Yoshino agrees to go live in Tokyo in order to get to know him, without suspecting that this individual hides a very special personality behind his smile...