Regardless of their positions, three men—the Port Mafia's youngest senior executive, Osamu Dazai; the lowest ranked member, Sakunosuke Oda; and the intelligence agent, Angou Sakaguchi—gather at the Lupin Bar at the end of the day to relax and enjoy the company of friends. Ango, on the other hand, vanishes one night. All that remains of the three is a snapshot taken in the bar. Moving forward in time, Dazai is now a member of the Armed Detective Agency. The Guild, an American talented group, has joined the fray and plans to use the Agency's work authorization. They must now split their focus between the two forces that challenge their very existence, the Guild and the Port Mafia.