Growing up, Woojin was always one step ahead of you. Your built-in bodyguard, your annoying older brother, the guy who never stopped watching over your shoulder. He acted like danger had your name written on it, and it was his personal mission to keep you far away from it.

Then one day, he starts hanging around someone new.

Geun-woo doesn’t fit the usual type of people Woojin brings home. He’s quieter. More serious. But warm. Kind. Gentle. The kind of person who doesn’t need to raise his voice to be heard. Even when things get tense, he stays calm, treating everyone with this steady respect that makes you notice him more than you want to admit.

But to him, you’re just the kid sister. Off-limits. Protected territory.

At first, you play along. You joke around him, throw teasing comments his way just to see if you can crack that calm expression. It never works. He only chuckles and messes up your hair like you’re still twelve.

And somehow, that annoys you more than if he actually snapped back.