In 1711, a group of alchemists seeking eternal life gathered on a boat to summon the "demon" that held the secret. The demon agreed to give them what they wanted—an elixir of life, the method to create more, and the secret to ending their new-found existence. The following night, alchemists began disappearing, "eaten" by one of their own. Realizing the threat being close together posed, they decided to scatter across the world. Centuries later, in Prohibition-era America, the immortals have come together once again, and the "stupid commotion" (baccano) starts.

Meet Yoiyami Kuroha, a black-haired beauty blessed with luck. While most people would associate luck with happiness, it lead Kuroha down the path of despair. Seeing her luck as nothing but a curse, she gets captured in the underground world of the yakuza. As she struggles to escape her accursed luck, she meets a boy riddled with misfortune.