Kang Jeong-won

Today is righteous Chae-young’s first day of her transferred school after beaten a bully to nothing. Despite the dad’s warning, she saves her classmate Jong-gu from bullies again. Fascinated by her, Jong-gu asks how to be strong like her.

A gym teacher and his female student look for her missing friend. But as they investigate, they find that her disappearance is a part of a larger conspiracy.

A warm, friendly, considerate person, Hee Jae is surrounded by people who claim to know and love her. The problem for Hee Jae is that she isn’t really sure if she really understands herself. On the other hand, Mi Na is Hee Jae's confident and energetic best friend and colleague at Play Books, a supplier of books and related products centered around sex and romance. While an expert in how to achieve physical pleasure, her understanding falls short on romantic relationships. When they find themselves told to take over hosting a sex and romance advice podcast, the two feel more than a little lost...

A story of love and friendship between five high school students from Seoyeon High School. Lee Ha-Min (Seo Ji-Hoon) appears like a bright person, but there is also darkness within his mind. Han So-Mang ( So Ju-Yeon) is a warm-hearted person, but she is also quite timid. Lee Jae-Min (Kim Min-Kyu) is a popular student with a painful past. He is kind to everyone around him. Yoon Bo-Mi (Kang Hye-Won) is a sweet, model student. Choi Jin-Young (Yoon Hyun-Soo) loves playing games. He can seem unfriendly and has a delicate personality.