Kim Seungmin, a 20-year-old college student, leads a double life. On campus, he’s quiet, diligent, and unbothered — but once the final bell rings, he trades his textbooks for bruised knuckles and a reputation that shadows him across the city. Raised to fight with no room for weakness, Seungmin doesn’t just survive; he dominates.

Meanwhile, Hwang Hyunjin, the 22-year-old nonchalant leader of one of Seoul’s most feared mafias, owns three skyscrapers and a sprawling mansion where his mafia lives like royalty. Cold, unreadable, and ruthless, Hyunjin feels like he’s seen everything — until one night, a flagged CCTV fight brings him face-to-face with the boy who fights like a demon… wearing brass knuckles and a careless smirk.

In a world of silent wars and blood-stained alliances, Hyunjin and Seungmin’s fates collide — and neither walks away untouched.

—

The black Escalade slid to a halt against the curb, its tinted windows throwing back the city’s neon haze.

Hyunjin sat in the backseat, legs spread lazily, head tilted against the leather as Bambam, from the passenger seat, glanced back at him.

“Another flagged location. Probably just some high school punks,” Bambam muttered, annoyed.

Yugyeom snorted from the driver’s seat. “Let’s just clear it fast.”

Hyunjin didn’t say anything. He never did unless he needed to. His dark gaze flicked lazily to the nearby alley where the fight was flagged. Another waste of time, probably.

Until he saw it.

Not kids. Not a high school scuffle.

One boy — college-aged, smaller frame, blood dripping from his lip — fighting ten men. And not just fighting — winning. His punches landed with bone-cracking precision, and on his fists glinted polished brass knuckles, catching every flicker of light.

One of the men he was fighting wasn’t random, either. Hyunjin narrowed his eyes — that was one of his own low-rank members, on the ground coughing up blood.

“What the hell,” Yugyeom muttered.

Bambam’s door slammed open first, but Hyunjin didn’t rush. He stepped out into the humid night, calm, expression unreadable. His black boots crunched glass as he approached, hands in his pockets, an almost bored look in his eye.