Original: 에이틴
Six Seoyeon High School students navigate the complexities of teenage life, first loves, and impending adulthood in this heartfelt coming-of-age drama.
An anonymous posted he likes Ha-na. The squad confronts Ha-min and asks which Ha-na he likes.
Do Ha-na gets a counsel about what she wants to do when she grows up. Students spread rumors of her copying Kim Ha-na.
Bo-ram gets dumped by her ex. The squad cheers her up.
Do Ha-na falls asleep while reviewing for the finals.
Everyone has their own jinxes for their own reasons. Kim Ha-na is a top student and she also has many jinxes before taking exams. These jinxes are very important to her so she always makes sure that she has done all the things she has to do before the exam. Kim Ha-na manages to get all things checked and everything seems to go fine until something happens to her.
School field day is around the corner and everyone is busy. Ki-hyun finds out the winning team gets prize money and put Si-woo's name on the basketball player list for the class because Si-woo used to play basketball professionally. Si-woo finds out, and he takes out his anger to Ki-hyun and demands to remove his name off.
Bo-ram is fascinated by basketball players and asks Do Ha-na to join the basketball club together. So Ki-hyun, Bo-ram, and Do Ha-na decide to join the club. Ki-hyun asks Si-woo to join also, but he refuses to join the basketball club. Meanwhile, Do Ha-na is always late to school and Si-woo offers to call her in the morning and go to school together.
At lunch, some boy asks Bo-ram about Do Ha-na if she has a boyfriend. And Kim Ha-na finds out Do Ha-na and Bo-ram decided to study at the same after school institute. Kim Ha-na feels left out and tries to hang out with Bo-ram and Do Ha-na but they already have plans. The next day, they decide to go watch a movie, but Ki-hyun tells Kim Ha-na that the other two already watched the movie she was trying to watch.
Bo-ram finds out Kim Ha-na was with Ha-min the last night. Do Ha-na is upset that Kim Ha-na wasn't being honest with her. Kim Ha-na also raises her voice about how she felt left out because they Do Ha-na and Bo-ram didn't tell her everything. On the other hand, Bo-ram is tired of always being the second, the middle one. She gets flustered between Kim Ha-na and Do Ha-na.
It's the field day at the school and everyone is excited. Bo-ram wins at the school e-sports competition and falls in love with the other player, Won-myung. Ki-hyun gets nervous she might really go out with Won-myung. Meanwhile, Si-woo and his basketball team lose at the final match. After the game, Ha-min asks Do Ha-na to hang out somewhere else with him, but Si-woo cuts in.
After Bo-ram won the prize money, Bo-ram and her friends go to eat fried chicken. While Bo-ram and Ki-hyun fight like a cat and dog, Ha-min talks to someone on the phone privately. Then everybody goes to the karaoke and bumps into Won-myung. Seeing Bo-ram enchanted by Won-myung, Ki-hyun starts to provoke her with nonsense.
The friends decide to go buy Ha-min's birthday gift. But Ki-hyun and Bo-ram lie to have their own date. Meanwhile, Do Ha-na finds out that the convenient store staff was actually Si-woo's brother and not Ha-min's. Ha-min and Kim Ha-na run into someone Ha-min knows, and Ha-min acts quite differently in front of that person. Si-woo tells Do Ha-na how he feels.
Do Ha-na uploads her drawing post on her social media and Si-woo calls her right after seeing her post. They have a small talk, feeling something strange. Although Si-woo has told her his feelings about her, Do Ha-na actually doesn't feel pressured or uncomfortable. A boy from the school comes up to her and asks her number, but Si-woo won't let it.
Bo-ram suggests to go on a trip altogether but there aren't many options they can choose. While they think up another plan hard, Ha-min gets a call from his mother. Ha-min's older brother is in Korea so they're having a family dinner. But Ha-min feels left out and leaves. Eventually, the friends end up in the backyard of Ki-hyun's house. Kim Ha-na also gets a call from her mother but she won't answer it.
Ki-hyun snatched a bottle of whiskey of his father's and brings it to their little trip. Ha-min and Kim Ha-na reveal their innermost thoughts and feelings. And all the lies are about to be disclosed. Si-woo gets wasted but his phone keeps ringing. Do Ha-na couldn't ignore it and answers the phone. And when the other person on the phone asked a question, she couldn't be honest.
Si-woo feels something is wrong with Do Ha-na and him. While he does not know what to do, his brother tells him to go and talk to her. He also mentions she wouldn't know if Si-woo won't talk. So Si-woo decides to tell his side of the story of how he started liking Do Ha Na to her. As he runs to see her, he sees Do Ha-na with someone else.
Ha-min confesses his feelings to his English tutor but she just snorts and doesn't take his confession seriously because she thinks of him like her little brother. Ha-min's mother finds out Ha-min's feelings for English tutor and tells him that she'll change the tutor. He runs away from home and heads to Si-woo's house. And Si-woo calls Do Ha-na.
Kim Ha-na runs into someone who recognizes her. But she remembers her name differently. Actually, contrary to what others have known so far, Kim Ha-na actually met Do Ha-na two years ago. And at that time, what Kim Ha-na saw in Do Ha-na was a confident person that she could never be. Kim Ha-na envied Do Ha-na because everyone seemed to like her no matter what she does or she doesn't.
Kim Ha-na keeps avoiding Do Ha-na and her friends from that day when some other girl called her Jo-yeon. Kim Ha-na envied Do Ha-na so much she decides to become different from Do Ha-na. But among all the things she's done to be different from Do Ha-na, there's nothing that she really wanted to do. She used to be an extra but now she's Kim Ha-na.
Do Ha-na feels good because she got pretty good grades at the mock exam. But Kim Ha-na starts to cry, saying she lost her notebook. The other students assume Do Ha-na stole her notebook since they haven't been getting along recently. Do Ha-na asks Kim Ha-na to deny it for her, but instead Kim Ha-na acts mean to her.
Si-woo gives Kim Ha-na her notebook back but she doesn't accept it. Si-woo also asks if she's going to apologize for accusing Do Ha-na of a false charge since they are friends. But instead, Kim Ha-na says she was never friends with her. Do Ha-na hears her while passing by and gets furious. Both of them start to say things that hurt each other.
Kim Ha-na calls in sick and stops coming to school. Do Ha-na and Bo-ram couldn't keep ignoring it and decide to visit Kim Ha-na at her house. However, they didn't even know where she lived all this time. After a long journey, they finally arrive at Kim Ha-na's house and meet Kim Ha-na and her grandmother.
Si-woo asks Do Ha-na to be his girlfriend but Do Ha-na tells him it'd be better if he has asked her out the day tomorrow since it's Proposal Day. So Si-woo asks her to promise him that she'd say yes if he wins at the final basketball match tomorrow. At the final match, Do Ha-na witnesses a girl named Lee Jeong-min.
Everyone watches a performance where a band is busking. The busker points at Do Ha-na and she gets to sing in front of a crowd. No one expects Do Ha-na would sing, but she starts to sing. As Do Ha-na sings, each friend looks back on their unordinary, one and only days of their lives as a teenager.
