In a reimagined Japan of Heisei 37 (2025), the government enacted the New Japan Special Economic Zone Act to stimulate the economy. However, this legislation backfired, leading to rampant turf wars between foreign communities vying for profits and a severe decline in public safety. Amidst this urban decay, a legendary assassin known as the "Dancing Death" (Danse Macabre) rises to infamy. With a fearsome reputation that ensures anyone targeted meets their end, the assassin’s true identity remains shrouded in mystery—known only as a beautiful "bad girl" who uses evil to counter evil.

The story focuses on a girl named Narumi, the cold and highly skilled killer behind the "Dancing Death" moniker. Struggling with brief moments of peace in her violent life, she accepts a new contract: the swift resolution of a government official's daughter kidnapping. She heads to a mountain warehouse where the hostage is being kept, but instead of a simple rescue, she walks into a chaotic three-way battle. A young gang is already at the warehouse attempting to steal valuables, and the Chinese mafia—the true orchestrators of the kidnapping—arrives to eliminate intruders and reclaim their property.

As the series progresses, Narumi and her associates begin investigating rumors of missing girls across the city. Their search for the truth leads them to the shadows of the Lau (Lau) organization, a powerful Chinese syndicate to which Narumi once belonged. This puts them on a direct collision course with Lau Hongfeng, a figure who once controlled Narumi and now obsessively hunts for her shadow. The narrative culminates in a final confrontation where the girl who seeks battle must ultimately turn her fangs against her former master to settle unfinished business in the underworld.