— Seul, 2025.

After finally starting university studies, Sunoo moved into a new house. He didn't move to a new apartment or an expensive house, but decided to stay in an old house that a close friend of his didn't use for anything at all for a better price. The house was slightly dusty, but nothing that needed deep cleaning — Sunoo's friend Jungwon already swept there whenever he had time. Around 6:00 PM on a Saturday, Sunoo arrived at the house, leaving his things in the car and going inside to explore. He turned on the yellowish light in each room of the house, stopping for a moment in a small room, a little dustier than the others. There were several old things piled up, among them a walkie talkie that had suddenly started beeping. Curious, Sunoo hurriedly took it, trying to hear something.