At the behest of the Queen, Earl Ciel Phantomhive hosts a lavish dinner party attended by several of the finest members of polite society—as well as struggling author, Arthur. But as the party reaches its high, a terrible murder takes place and none other than the Earl himself is suspected of the crime. As a violent storm rages on outside, the death count continues to climb. The Phantomhive household and their eminent guests find they must cooperate in order to solve this mystery before they too fall prey to the mysterious murderer. However, it seems that not even the perfect butler, Sebastian Michaelis, is safe from this horror.

With the conclusion of her favorite romance manga, Fuuko Izumo is ready to end her life of misery and loneliness having long accepted her fate of never being able to experience passionate love like fictional characters. Cursed with unluck, anyone Fuuko touches is in grave danger of experiencing unimaginable calamity. While the possibility of imminent danger would have most sane people run in the opposite direction, Undead has other ideas. He is an immortal being with superhuman regenerative powers desperately seeking death, which has always eluded him. When their paths finally cross, Undead sees an opportunity to finally end his suffering by using Fuuko's unluck. But before Undead can unlock the full potential of Fuuko's power to trigger the final devastating blow, the duo must first fend off a murderous secret organization hell-bent on exterminating those with special abilities.

After seeing enough death and tragedy, the immortal Fushi secludes himself on an island, defending himself from enemy Nokkers. However, instead of attacking Fushi in isolation, Nokkers begin targeting the settlements outside of his reach in hopes of luring him out. Soon, a group known as the Guardians—led by Hisame, the descendant of the deceased warrior Hayase—finds Fushi. Inspired by how Fushi protected Janada Island from the Nokkers years ago, the Guardians have grown a considerable following and are recognized throughout the world. Initially reluctant, Fushi allows the Guardians to accompany him to the site of the Nokkers' recent attack. In their village, Fushi meets a few valuable allies, both new and old. But as the conflict with the Nokkers only leads to more loss, Fushi must find the inner strength to face his inevitable sorrow.

A powerful necromancer known as the Corpse God dies during a legendary battle, only to be reborn as Polka Shinoyama, a young boy in modern-day Tokyo. In the process of trying to adapt to his new physical body, he gets targeted by various groups that deal with the supernatural. Among them is Misaki Sakimiya, a high school girl who can see spirits and is out for his blood from the very moment they meet. Attempting to make sense of this situation where unknown parties want him dead, Polka eventually meets Takumi Kuruya, a contractor skilled in surveillance and hacking, and Lisa Kuraki, a crime boss operating out of Shinjuku. Alongside these—and other unexpected—allies, Polka braves danger to reveal the truth of his reincarnation and the fate awaiting the world he now lives in.