Daehyun and Youngjae are famous radio show hosts of the programme Horror Hotline, where they take in stories from the public about freaky sights people have spotted over the years. One day, they get a phone call from an anonymous person, telling them about a murder that happened two decades ago at a kindergarten nearby. Intrigued, Daehyun proposes to Youngjae that they check it out together, secretly wanting to spend more time with Youngjae outside of work. 

What was initially just something lighthearted and to satiate curiosity has the two radio hosts uncovering a case they should have never pried.