Three years ago, a disappearance known as the Joker Case went unsolved, and the file closed. Renewed interest in the case demands a second examination of the evidence.<br />Investigator Kinoshita Ichiro from the Public Security Bureau of the Tokyo Metropolitan Police Department is called on for a reunion of the investigation. However, he is assigned a completely different mission. His assignment is to spy on a gang clan led by its young head, Hanabusa Shiro. A man of mystery, Shiro has risen to the rank of Wakagashira (young leading subordinate in the yakuza group) in three short years.<br />In the course of his mission to get close to Shiro, Ichiro learns a shocking fact steering him to draw up a fake lover's contract with Shiro. Their undercover operation gradually leads to an incident sure to shake up both the nation and their destinies.<br />
