Sseo-ni

Im Na-mi, a wealthy but depressed housewife, feels disconnected from her family and lonely in her seemingly perfect life. Her husband and daughter are indifferent towards her, and she eats breakfast alone every morning. One day, she visits her mother in the hospital and recalls her high school days upon seeing the name "Ha Chun-hwa" on a patient's room. Im Na-mi then visits her old teacher at the high school she once studied at and is then taken back to her teenage years, where she is introduced as a new student in an all-girls high school in Seoul. Initially ridiculed for her country accent and appearance, she befriends Ha Chun-hwa and joins her group of friends called "Sunny." The group consists of six other girls: eyelashes-obsessed Kim Jang-mi, foul-mouthed Hwang Jin-hee, writer's daughter Seo Geum-ok, beauty queen wannabe Ryu Bok-hee, and the school goddess but distant Jung Su-ji. They bond over shared experiences and adventures, including a memorable rivalry with another school group at a police riot. Na-mi also experiences her first love with Han Joon-ho, Jang-mi's brother friend, but ends her feelings towards him when she sees him with Su-ji.