该剧是讲述危险且不成熟的「Pre-青春」们直面这个世界的感性青春剧。18岁，因为细微的事情也会被卷入感情的旋涡，和谁都会产生小摩擦。将真实地描写18岁的这些瞬间，引发观众的共鸣。对习惯性孤独的18岁少年崔俊宇而言寂寞就是日常。他不擅长表达自己的情绪，也不努力去和别人产生共鸣，但有着呆萌可爱的反转魅力，俊宇以转学为契机开始发生变化。俞秀彬是在妈妈的野心和极端逼迫下诞生的优等生。是在妈妈全方位的完美管理下，没有明确的梦想和目标，活得很茫然的18岁少女，秀彬真正的梦想就是独立生活，当她遇到俊宇之后，她的生活开始发生了小变化。马辉英是外表看起来很完美但内心有阴影的人物。他外表出众，性格绅士，是大家都很信赖的人物。在他完美的外表下，其实隐藏着自卑的心，看上去很坚强的他其实很胆小，18岁少年马辉英因为车俊宇这个强力的转校生的出现，他的铁壁高墙开始崩塌。
十八岁的瞬间 (季节 1)
The Nameless Kid, Choe Jun-u 8.0
播出日期: 2019-07-22
运行时间: 68 min
概述: 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.
A Moment I Want to Run Away 8.0
播出日期: 2019-07-23
运行时间: 64 min
概述: 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.
It Always Rains on a Sad Day 7.0
播出日期: 2019-07-29
运行时间: 67 min
概述: 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.
Happiness and Sadness Come and Go Instantly 8.0
播出日期: 2019-07-30
运行时间: 66 min
概述: Su-bin and Jun-u continue practicing their English for the upcoming evaluation. Sin Jeong-hu writes a letter, and makes a heartfelt apology.
After that Long and Sad Day 7.0
播出日期: 2019-08-05
运行时间: 67 min
概述: 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.
The Timing of Action and Reaction 8.0
播出日期: 2019-08-06
运行时间: 64 min
概述: 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.
Romeo and Juliet 9.0
播出日期: 2019-08-12
运行时间: 61 min
概述: 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.
The Moment of Your First Love 9.0
播出日期: 2019-08-13
运行时间: 62 min
概述: 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.
I'm Sorry 7.0
播出日期: 2019-08-19
运行时间: 67 min
概述: 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.
The Night That Will Never Return 7.0
播出日期: 2019-08-20
运行时间: 58 min
概述: When the class goes on a trip together, the students bring with them a tangled mess of relationship and personal dramas.
The Emotions That I Got to Know Through You 7.0
播出日期: 2019-08-26
运行时间: 62 min
概述: 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.
Being More Mature Than Adults at the Age of 18 8.0
播出日期: 2019-08-27
运行时间: 64 min
概述: 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.
I Should Still Like You 6.0
播出日期: 2019-09-02
运行时间: 68 min
概述: Finals approach, Song-hui's disapproval forces Su-bin and Jun-u apart, and Han-kyeol tracks down Hwi-yeong's old teacher.
Happy Birthday to You 8.0
播出日期: 2019-09-03
运行时间: 63 min
概述: Everyone worries when the rumor about Hwi-yeong gets him into real trouble. Jun-u tells Han-kyeol about his newfound goal.
Ways to Embrace Your Scar 9.0
播出日期: 2019-09-09
运行时间: 66 min
概述: Song-hui remains stubborn about Su-bin and Jun-u, who enters an art academy. The school board investigates Hwi-yeong's case.
This Goodbye Isn't Forever 8.0
播出日期: 2019-09-10
运行时间: 66 min
概述: Hwi-yeong makes peace with the others -- and himself. Jun-u realizes his mother's situation, and must break difficult news to Su-bin.
季
集 16