At Eighteen - Season 1

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.

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.

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.

Su-bin and Jun-u continue practicing their English for the upcoming evaluation. Sin Jeong-hu writes a letter, and makes a heartfelt apology.

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.

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.

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.

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.

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.

When the class goes on a trip together, the students bring with them a tangled mess of relationship and personal dramas.

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.

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.

Finals approach, Song-hui's disapproval forces Su-bin and Jun-u apart, and Han-kyeol tracks down Hwi-yeong's old teacher.

Everyone worries when the rumor about Hwi-yeong gets him into real trouble. Jun-u tells Han-kyeol about his newfound goal.

Song-hui remains stubborn about Su-bin and Jun-u, who enters an art academy. The school board investigates Hwi-yeong's case.

Hwi-yeong makes peace with the others -- and himself. Jun-u realizes his mother's situation, and must break difficult news to Su-bin.