"Taboo Tattoo" is a manga series that blends action, supernatural elements, and military intrigue. The narrative centers on Seigi, a skilled martial artist who lives a modest life with his grandfather. One day, Seigi intervenes in a street altercation and saves a homeless man, who, in gratitude, gives him a mysterious tattoo. This tattoo, known as a "Taboo Tattoo," grants Seigi extraordinary powers, including the ability to manipulate time and space. However, the tattoo also draws him into a dangerous world of international conflict and covert operations.

The tattoo is revealed to be a weapon developed by the United States as part of a secret military project. Seigi becomes a target for various factions seeking to control or eliminate the tattoo's power. Among these factions is the Kingdom of Selinistan, a small but technologically advanced nation that opposes the U.S. and seeks to use the tattoos for their own purposes. Seigi is pursued by elite agents, including Bluesy Fluesy, a skilled fighter and former U.S. operative who initially appears as an antagonist but later becomes an ally.

As the story progresses, Seigi learns more about the origins and implications of the tattoos. They are tied to a phenomenon called the "Seventh Code," a powerful force capable of reshaping reality. The tattoos are fragments of this code, and their wielders, known as "Seal Bearers," possess immense but unstable power. Seigi's journey involves uncovering the truth behind the Seventh Code while navigating alliances and betrayals among the various factions vying for control.

The series features a diverse cast of characters, each with their own motivations and connections to the tattoo project. Izzy, a young girl with a tragic past, becomes a key figure in Seigi's life, as her own tattoo holds significant importance. Other characters, such as Tom Shredfield, a ruthless U.S. operative, and Princess Aryabhata of Selinistan, add layers of complexity to the narrative, highlighting the moral ambiguities and ethical dilemmas surrounding the use of the tattoos.

"Taboo Tattoo" explores themes of power, responsibility, and the consequences of technological advancement. The plot is driven by high-stakes battles, political maneuvering, and the personal struggles of its characters as they grapple with the weight of their abilities and the choices they must make. The series balances intense action sequences with moments of introspection, creating a dynamic and engaging story that delves into the darker aspects of human ambition and the cost of wielding extraordinary power.