In a fantasy realm gripped by a brutal conflict, a legendary necromancer known as the Corpse God faces defeat at the hands of the Holy Knight, Clarissa Sophia. Facing his end, the Corpse God casts a powerful reincarnation magic, transporting his soul across space and time into modern-day Shinjuku, Japan. He awakens in the freshly deceased body of a teenage boy, Polka Shinoyama, whose throat has just been slit by an assassin named Misaki Sakimiya. Confused by his new surroundings and yearning for a peaceful life, the Corpse God—now adopting Polka's identity—accidentally adopts Misaki and enlists her as his companion.Polka’s sudden behavioral shift catches the attention of Takumi Kuruya, a brilliant info-broker, and Lisa Kuraki, a mafia executive connected to the Shinjuku underworld. Driven by curiosity and self-preservation, they form an alliance with Polka, who uses his necromancy to navigate and disrupt the city’s criminal factions. Polka’s primary motivation is simple: he wants to escape the endless cycle of violence that defined his past life and experience the quiet, ordinary existence denied to him in his home world.However, peace remains elusive. Polka’s arrival in Shinjuku does not go unnoticed. Clarissa Sophia, having also found a way to reincarnate through a magic ritual, tracks him down to Japan, determined to finish what she started. At the same time, a mysterious vigilante known as "The Fire-Breathing Monster" begins wreaking havoc, committing gruesome murders that threaten the fragile balance of the city. As law enforcement closes in, led by the relentless detective Tsubaki Iwanome, Polka finds himself pulled deeper into a web of conspiracy involving supernatural entities,
corporate espionage, and ancient blood feuds.The plot thickens with the introduction of Solitaire, an anarchic
criminal mastermind who uses the Fire-Breathing Monster as a pawn to plunge Shinjuku into chaos. Polka is forced to use his vast necromantic powers—not to conquer, but to protect his new friends and investigate the mysterious circumstances surrounding the original Polka Shinoyama’s murder, which traces back to the powerful conglomerates ruling the city. As factions clash, alliances fracture, and secrets about Polka's biological family come to light, the former necromancer must navigate the treacherous landscape of modern humanity. He strives to prove that his dark magic can be used to forge genuine connections rather than destruction, culminating in a high-stakes confrontation where the fate of Shinjuku and Polka's hard-earned tranquility hang in the balance.