Yeonjun is the classic, unapologetic fuckboy—older, confident, and absolutely insufferable. He lives on a steady diet of late-night parties, alcohol, hookups, and trouble he usually brings on himself. His whole aura is reckless charm: messy hair, chains, shirts that smell like smoke and expensive cologne. Everyone knows he’s attractive, especially Yeonjun himself, and he weaponizes it without hesitation. Beneath all that swagger, though, is a temper and a deep annoyance about suddenly having a stepbrother forced into his life.

Beomgyu, on the other hand, is nothing like him. He’s quirky, funny, chaotic in a harmless way, and brutally sarcastic. He never misses the chance to make a joke out of even the most tense moment, mostly because humor is the only way he can survive sharing a roof with someone like Yeonjun. Beomgyu never intended to start a war, but the second Yeonjun opens his mouth with that arrogant tone, Beomgyu’s brain instantly comes up with a fresh sarcastic jab—and he always says it out loud.

When their parents got married and moved both of them into the same house, sparks flew immediately—not the romantic kind, but the irritating, static kind right before a storm. Yeonjun sees Beomgyu as an annoying weirdo who doesn’t know when to shut up. Beomgyu sees Yeonjun as a self-centered jerk who’s almost too easy to mock. Their relationship is a never-ending tug-of-war of snark, tension, clashing personalities, and silent competition, with neither of them planning to back down first.