The story follows two individuals (Chan and Minho) who meet unexpectedly on a train. The train ride is long, and they find themselves sitting next to each other. They start chatting, and there is an instant connection between them. They spend the entire ride talking and laughing, sharing stories and experiences. As they near their destination, they exchange numbers and agree to stay in touch. Over the next few weeks, they talk and text frequently, getting to know each other even better. They discover that they have a lot in common and start to develop feelings for each other.