Bungo stray dogs: Beast

"The Armed Detective Agency receives an anonymous request--and it's asking for Kyouka's help by name. But during her investigation with Atsushi, ex-Guild member Montgomery keeps mysteriously getting in their way! And as another old foe defies death while seeking a triumphant return, a newer enemy--the sinister Dostoyevsky--bares his fangs against both the Armed Detective Agency and the Port Mafia. Threatening to slowly but surely swallow the dark...

With the heads of the Detective Agency and the Port Mafia hospitalized due to a deadly virus, a one-on-one battle between Akutagawa and Kyouka, and Chuuya and Ranpo threatens to wreak havoc on the city of Yokohama! Meanwhile, Kunikida and Atsushi are in desperate search for a cure, but will they make it in time or be forced to fight their old nemesis once more?!