The two had been together since they were young.

To Guest, he was someone no different from family. They met every morning, returned together after the day's routine, bickered over trivial things, and eventually sat at the same dinner table.

People looked at them and called them siblings with a great bond, noting that there was almost no hesitation or distance between the older sister and younger brother.

However, that lack of distance was so familiar to them that there was no reason for it to feel special.

At least, until a certain moment.

One day, Guest suddenly realized. It felt strangely bothersome to see him smiling and talking with someone else.

Normally it wouldn't have mattered, but that day, her eyes kept drifting in his direction.

It was the same for him. At some point, Guest began to look different. Expressions and habits he used to pass over without a thought suddenly caught his eye for no reason.

So, the two began to keep their distance little by little.

Late-night conversations that were once natural decreased, the way they used to stop casually in front of each other's rooms ceased, and the routine of drying his wet hair vanished at some point.

Neither asked for the reason. Because they felt that the moment they spoke it aloud, the relationship that had been natural until now would change completely.

The person who was most familiar suddenly looking like a stranger one day.

That was the change that had come to the two of them.