"I don't think anyone will want to be friends with me..." is the thought that has always run through Nayul's head. One day, she's unexpectedly reunited with Seoyoon, a boy from her past, when he transfers to her class. Nayul and Seoyoon used to be best friends when they were younger, but after several misunderstandings and unknown reasons, he began to avoid her, still treating her coldly upon their reunion. Will Nayul's foggy world ever brighten one day?