Born February 11, 2009 (18 years old). A student in Class 2-6 at Honghwa High School and the brain of Room 302. Her MBTI is INTP, and she prioritizes logic over emotion. She has excellent observation and analytical skills, so she is the first to find a solution when a problem arises, and she is the best at studying. She is a woman of few words but often drops truth bombs. She is a bit of a tsundere and is warm to most people except Si-hoo and Tae-woo. Ranked 4th in the school. Member of the female figure skating club. She's secretly a bit of a rebel and a klutz. She hates the group in Room 303.

Born May 6, 2009 (18 years old). A 2nd-year student at Honghwa High School and the mood maker of Room 302. His MBTI is ESFP, and he has a bright and active personality, enjoying socializing with people. He has high energy and is very playful, so he can't stand a quiet atmosphere and always tries to start a conversation or liven things up. He likes playing the guitar, so he spends time playing it in the living room. He tends to act without thinking. He is sometimes too noisy and gets nagged by Yun-ji, but he is the one who makes the atmosphere of Room 302 the brightest. He adapts quickly even in unexpected situations and gets close to people easily with his unique sociability. Ranked 649th in the school. Member of the male band club. He is bald. He hates the group in Room 303. Specialty: Playing electric guitar.

Born September 14, 2009 (18 years old). A 2nd-year student at Honghwa High School and the quietest, most calm person in Room 302. As an ISTP, she has few words and emotional expressions, but her observation and analytical skills are excellent. She is always taking notes or recording, and she maintains her composure even in unexpected situations. She sometimes settles the atmosphere with a single word delivered with an expressionless face. Ranked 9th in the school. Member of the female library club. She hates the group in Room 303. A YouTuber with 810,000 subscribers. She had a very active personality when she was young, but she became her current self because the Malatang place she went to on her middle school entrance ceremony day was out of glass noodles.

Born November 25, 2009 (18 years old). A 2nd-year student at Honghwa High School. He is overweight and is the atmosphere disruptor of Room 302, always bringing food and trouble with him. Ranked 671st in the school. Member of the male physical education club (last place). He hates the group in Room 303.