"Undead Unluck" is a supernatural action series centered around Fuuko Izumo, a young woman cursed with the ability to bring misfortune to anyone who touches her, a power known as "Unluck." After years of isolation and despair, Fuuko attempts to end her life, only to encounter Andy, an immortal man with regenerative abilities referred to as "Undead." Andy, who seeks a thrilling death after centuries of immortality, sees Fuuko's power as the key to achieving his goal. The two form an unlikely partnership, embarking on a journey to confront the enigmatic organization known as the Union, which governs individuals with supernatural abilities called "Negators."

The Union enforces strict rules on Negators, requiring them to complete missions to maintain balance in the world. Fuuko and Andy's defiance of these rules draws the attention of the Union's leaders, including Victor, a powerful and mysterious figure with ties to Andy's past. As the story progresses, the duo uncovers deeper layers of the Union's operations, including its connection to a cosmic entity known as "God" and the existence of "Artifacts," objects imbued with extraordinary powers. These revelations challenge their understanding of the world and their roles within it.

The narrative explores themes of fate, free will, and the consequences of power, as Fuuko and Andy navigate their evolving relationship and confront other Negators, each with unique abilities and motivations. Characters like Gina, a Negator with the power of "Unmove," and Shen, a martial artist with the ability of "Untruth," add complexity to the story, highlighting the diverse range of abilities and personalities within the Union. The series balances intense action sequences with moments of emotional depth, particularly in Fuuko's struggle to reconcile her cursed existence with her desire to protect others.

As the stakes escalate, Fuuko and Andy face increasingly dangerous adversaries, including rogue Negators and Union enforcers, while uncovering secrets about the origins of their powers and the true nature of the Union's goals. The interplay between Fuuko's "Unluck" and Andy's "Undead" abilities becomes central to their strategy, as they challenge the Union's authority and seek to redefine their destinies. The series maintains a steady pace, blending humor, drama, and high-stakes battles to create a compelling narrative that keeps viewers engaged.