Episode guide
At Eighteen: Season 1
16 episodes · premiered Jul 22, 2019
A misunderstood loner is drawn out of his shell after transferring to another high school, where he comes across new ordeals -- and first love.
- Episode 1: The Nameless Kid, Choe Jun-u Jul 22, 2019 · 1h 8m Not long after arriving at a new high school, where he's shown around by star student Ma Hwi-yeong, Choe Jun-u faces an unfair accusation.
- Episode 2: A Moment I Want to Run Away Jul 23, 2019 · 1h 4m Jun-u prepares to transfer schools again. Yu Su-bin doesn't believe Jun-u took the watch. Hwi-yeong won't own up to what he did.
- Episode 3: It Always Rains on a Sad Day Jul 29, 2019 · 1h 7m Jun-u beats out Hwi-yeong to pair up with Su-bin for a class assignment, and receives an urgent call about an old friend.
- Episode 4: Happiness and Sadness Come and Go Instantly Jul 30, 2019 · 1h 6m Su-bin and Jun-u continue practicing their English for the upcoming evaluation. Sin Jeong-hu writes a letter, and makes a heartfelt apology.
- Episode 5: After that Long and Sad Day Aug 5, 2019 · 1h 7m Jun-u's outburst of rage panics Hwi-yeong, who has something to cover up. O Han-kyeol visits someone who can testify to the truth.
- Episode 6: The Timing of Action and Reaction Aug 6, 2019 · 1h 4m Fighting with her mother, Su-bin doesn't go home. Determined to reveal Hwi-yeong's true nature, Jun-u starts to gain insight into his behavior.
- Episode 7: Romeo and Juliet Aug 12, 2019 · 1h 1m Su-bin and Jun-u can't stop thinking about each other -- but don't know what to do about it. Hwi-yeong agonizes over one wrong answer on a math test.
- Episode 8: The Moment of Your First Love Aug 13, 2019 · 1h 2m Even as Su-bin learns she's not the only one who likes Jun-u, she's excited for their first date. Jo Sang-hun goes up against Hwi-yeong's parents.
- Episode 9: I'm Sorry Aug 19, 2019 · 1h 7m Hwi-yeong sends Su-bin something that cuts her date with Jun-u short. Han-kyeol turns away a bribe. Yun Song-hui searches for a driver.
- Episode 10: The Night That Will Never Return Aug 20, 2019 · 58m When the class goes on a trip together, the students bring with them a tangled mess of relationship and personal dramas.
- Episode 11: The Emotions That I Got to Know Through You Aug 26, 2019 · 1h 2m Han-kyeol deals with a petition to replace him. Hwi-yeong removes Su-bin from the tutor group, which bothers Song-hui more than it does her.
- Episode 12: Being More Mature Than Adults at the Age of 18 Aug 27, 2019 · 1h 4m A rumor about Hwi-yeong's grades being rigged spreads like wildfire. Su-bin hesitates to tell Song-hui something, and meets with her father.
- Episode 13: I Should Still Like You Sep 2, 2019 · 1h 8m Finals approach, Song-hui's disapproval forces Su-bin and Jun-u apart, and Han-kyeol tracks down Hwi-yeong's old teacher.
- Episode 14: Happy Birthday to You Sep 3, 2019 · 1h 3m Everyone worries when the rumor about Hwi-yeong gets him into real trouble. Jun-u tells Han-kyeol about his newfound goal.
- Episode 15: Ways to Embrace Your Scar Sep 9, 2019 · 1h 6m Song-hui remains stubborn about Su-bin and Jun-u, who enters an art academy. The school board investigates Hwi-yeong's case.
- Episode 16: This Goodbye Isn't Forever Sep 10, 2019 · 1h 6m Hwi-yeong makes peace with the others -- and himself. Jun-u realizes his mother's situation, and must break difficult news to Su-bin.