Kang Haein was the exact definition of a wallflower. She lived on the sidelines, didn't like attention and worried too much. She wrote letters to herself as her way to get her thoughts out. She never told anyone or let anyone see. Choi Beomgyu, one of the school star athletes and most popular boys, found one of her letters. He started breaking into her locker to read the letters every time there was a new one. He grew concerned about her and wanted to protect her, he wanted to know why she was so broken and who hurt her, he wanted her to know he was there for her - be her shoulder to lean on. How would this friendship work out with Hyejin being as shy and quiet as she is, never getting close to anyone? How would this friendship last if Haein came to find out the truth about Beomgyu stealing and reading her personal letters?