Bungo Stray Dogs on Stage: STORM BRINGER

Before he joined the Armed Detective Agency, Osamu Dazai was the youngest-ever executive with the Port Mafia, the most notorious underground 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 called Mimic. At last, the reason why Dazai parted ways with the Port Mafia is revealed!

Doppo Kunikida is an idealist and a straight-laced detective at the Armed Detective Agency, an organisation that takes on dangerous jobs even the police won't handle. 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.

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. However, with ominous rumors about Mori's deceased predecessor as well as the mysterious being called Arahabaki spreading throughout Yokohama, the duo must put aside their differences and get to the bottom of things. Before they achieved infamy as the fearsome pair Twin Dark, Dazai and Chuuya were just boys. Was their first encounter a harbinger of hope or an ill omen of things to come...?

A criminal organisation called the Rats in the House of the Dead makes its existence known to the Armed Detective Agency. Little is known about it and its alleged leader, Fyodor Dostoevsky, but a downward spiral begins when the leaders of the Agency and the Port Mafia are infected with a virus named Cannibalism and are left gravely ill. With just 48 hours to save their leaders, a blood feud breaks out between the organisations of Yokohama.