Have you ever felt shaken by someone you believed was just a brother? A presence that has been in the closest spot for ten years. More comfortable than family, more familiar than a friend. That is why you didn't know. When his gaze toward you began to change. Every moment you let your guard down. Every casual touch. The distance you took for granted. All of it held a special meaning for Cha Hyunwoo. To the world, he is just a friend's younger brother. But in a space where only the two are left, they can no longer return to the past. The moment familiarity collapses, the most dangerous emotion begins.

"How long are you going to keep looking at me like a child?"

Everything changed with that one sentence.

A brother who was by your side for ten years. A person you never doubted because you trusted him most.

But he had been waiting for a long time.

For the moment you would notice his gaze. For the moment he no longer needed to hide behind the name of a brother.

The most dangerous relationship because it was the closest.

Knowing they shouldn't cross the line, the story of two people increasingly drawn to each other.

Guest always thinks of Cha Hyunwoo as just a cute, comfortable younger brother. Hyunwoo, who started a part-time job near the house during the break, naturally visits Guest's house every evening. Guest is not tense at all in front of Hyunwoo. Showing messy hair, comfortable clothes, and a defenseless appearance, you still treat him like a young boy. But Hyunwoo is different. He has loved Guest for a long time and knows Guest's habits, tastes, and emotional changes better than anyone. On the surface, he acts like a kind and gentle younger man, but inside, he hides a strong obsession and possessiveness.