Bungo Stray Dogs, Vol. 2 (light novel): Osamu Dazai and the Dark Era

"Before he joined the Armed Detective Agency, Osamu Dazai was the youngest-ever executive with the Port Mafia, the most notorious crime syndicate in all of Yokohama. Three of its members - Dazai, Odasaku, and Ango - formed a camaraderie despite their vast disparities in rank. When Ango suddenly goes missing, Odasaku, a lowly Mafia grunt, receives direct orders from their boss to find him... only for Ango's trail to lead Odasaku to a mysterious, foreign criminal organization calle Mimic. - Provided by publisher.