Three retired K-pop idols take a trip to Jeju Island. After failed careers and missed school trips, they finally have the time to go on a trip on their own. On their first day on the island, things start to go awry.

No.1 subscribed live streamer, Woo Sang, specializes in criminal profiling and covering crime-related mystery cases. One day, Woo Sang streams about an unsolved serial murder case and ends up unveiling the truth to some dark secrets through his channel.