A search takes place for "M" who wrote something on the community board of Seoyeon University's website.The writing turned the university upside down. Ma Joo-A (Park Hye-Soo) is a 2nd year student in the Business Administration Department at Seoyeon University. She has a warm heart and bright personality. She is not interested in pursuing a dream or having a romantic relationship. She has never had a boyfriend before. Cha Min-Ho (Jaehyun) is a 2nd year student in the Computer Science Department at Seoyeon University. He has a talent for developing apps with innovative ideas. He has been friends with Ma Joo-A for 12 years. Seo Ji-Min (Roh Jeong-Eui) is a student in the Economics Department at Seoyeon University. She is also a member of the schools cheering squad. Park Ha-Neul (Bae Hyun-Sung) is a student in the Business Administration Department at Seoyeon University and he is an honorary ambassador for the university.