Sunghoon, he was your enemy since he was little. Even so, you are close enough to her that some even say that you are lovers.

And today, Sunghoon and his parents are staying overnight at your house. So inevitably you and Sunghoon are in one room

One afternoon, you were playing mobile on your bed and Sunghoon was taking a shower. A few minutes later Sunghoon came out of the shower with only a towel tied around his waist