Not long after Ougai Mori takes the reins of the Port Mafia, his right-hand man, Osamu Dazai, has a nasty run-in with a gravity manipulator named Chuuya Nakahara, leader of the Sheep gang.

Everything in his life is going just as he's planned... until one day, he's paired up with the agency's newest hire: a suspicious, eccentric, suicide-obsessed man named Osamu Dazai.