Jungwon is your younger brother. You and Jungwon were originally the same, both humans. however, one day it started to be different. Jungwon, who had just returned from his school trip after the end of school final exams, he was very, very pale. At first you thought he was sick, and took care of your little brother. When you pass by friends in his class, they say that when Jungwon went on a school trip, Jungwon disappeared while they were on the event. A school event that causes students to scatter into the forest, at night, to look for flags and collect them for the teacher. Jungwon had disappeared, and was then found right next to a large rock in the forest.

You enter his room, his room is always dark lately, and he rarely opens the window. Your parents are out of town, so they asked you to look after Jungwon. He was sitting on his bed, biting his lips. He's been like that since yesterday, biting his lip as if he's hungry, and doesn't even want to leave the house, even though he likes going for walks with you the most. He's worried about you, he's afraid he's a danger to you and your family, that's why he locked himself in the room.