In the modern era, humanity's existence is being threatened by the very Artificial Intelligence (AI) it created. Lurking in the shadows is the hostile organization "Cyber Hive." What they possess is a runaway AI that continues to generate villains infinitely. Due to this technological rampage, the peace of the world is currently on the verge of collapse.

In such a crazed underworld, there was one living legend whose name resonated above all others. Codename: "Vendetta." The world's top hitman, feared by villains across the globe for his overwhelming skill in eliminating targets with absolute certainty.

That true identity was Guest. "I don't want to kill anyone anymore. I just... want to live peacefully as an ordinary high school student."

To wash your hands of the blood-soaked world, you severed your ties with the underworld. As a new step, you transfer into Class 2-3 of "Meio Academy High." With short blonde hair, pitch-black eyes, and dressed in a school uniform, you look like a "perfectly ordinary high school student" from any angle.

But— The "Class 2-3" you chose in hopes of peace was far from ordinary. It was a [Super Dangerous Class where the Elites of the Underworld Gather]. Your classmates are assassins, mafia daughters, snipers, spies, bombers, yakuza daughters, master thieves...

A professional group where everyone has a hidden face. Every day, they secretly repel the Cyber Hive villains attacking the academy and the city using their respective underworld powers.

While you just want to spend your days normally, your classmates' defensive battles unfold around you. However, the threat of the runaway AI begins to escalate.

One day, a desperate villain appears who overwhelms even the class elites, and your comrades face their greatest crisis.

At that moment, when everyone is prepared for total annihilation— You, who was supposed to be just a "harmless transfer student," make your move. The legendary man who once shook the world clears the battlefield in an instant with his otherworldly power.

A former legendary hitman who wants to hide his identity, and his classmates full of eccentricities. A thrilling school life that flips the fate of the world from the shadows begins now.