Gong Ju Young is a 17-year-old high school student who thinks he has found love at school when he falls in for Wang Ja Rim at first sight. But winning her heart won’t be easy. Wang Ja Rim has earned a reputation for being cold and aloof – and, at first, seems totally unimpressed by Gong Ju Young’s garish displays of affection. But Gong Ju Young won’t be deterred so easily. Persistence is the key, he thinks – and, over time, Wang Ja Rim starts to open up to her classmate. Gong Ju Young’s best buddy since elementary school is Lee Kyung Woo. Will he prove to be a help to Gong Ju Young in his quest for Wang Ja Rim’s heart – or a hindrance?
Episode 1
On the first day of school, high school freshman Joo-young falls deeply in love at first sight with the pretty but aloof Ja-rim and thinks they are destined for one another.
Episode 2
Joo-young surprises Ja-rim with loads of lollipops on White Day. Ja-rim gets annoyed as Joo-young keeps on following her and asking for her number.
Episode 3
Joo-young, Kyung-woo and Byung-hoon prepare for a dance number at the school retreat talent show. When students arrive at the retreat's venue, Joo-young suddenly goes missing.
Episode 4
Joo-young publicly confesses to Ja-rim at the talent show.
Episode 5
Joo-young overhears Ja-rim telling her friends she went along with Joo-young's public confession because she pitied him. Hurt by her words, Joo-young keeps on whining to his friends not to pity him.
Episode 6
Joo-young decides to formally confess to Ja-rim and ask her to be his girlfriend on Rose Day. A female senior tries to stop Joo-young from going out with Ja-rim.
Episode 7
Joo-young is in ecstasy when Ja-rim finally accepts him as her boyfriend, but she remains as cold as before. Ja-rim flat out rejects Joo-young's date plans and reminds him of their upcoming exams.
Episode 8
Joo-young manages to get angry at Ja-rim and complains for being treated so badly.
Episode 9
Kyung-woo's friends discover that he is working in a café and is popular among female customers. They pay him a visit one day, unknowing that it is Byung-hoon's birthday. Byung-hoon innocently assumes they are preparing a surprise for him.
Episode 10
Joo-young, Ja-rim and their friends go on a trip to Byung-hoon's countryside home. When they get thirsty while harvesting chilies, Joo-young goes to fetch water but returns drunk after not being able to stop himself from drinking alcohol.
Episode 11
Before going home, Joo-young, Ja-rim and their friends clean Byung-hoon's grandparents' house and have fun for the last time. Ja-rim tries to make hangover soup for Joo-young.
Episode 12
Joo-young goes out for a date with Ja-rim, who is unknowing that it is Joo-young's birthday.
Episode 13
Joo-young asks Ja-rim to cheer for him in a recreational basketball match with Jung-woo. Ja-rim meets Jung-woo and runs away in surprise. A misunderstanding ensues and Ja-rim finds it hard to explain to Joo-young the truth of her past with Jung-woo.
Episode 14
Joo-young receives a call from Min-ji. The day after, Joo-young goes to play basketball with Jung-woo in casual attire and behaving strangely.
Episode 15
Joo-young has an upcoming weekend date with Ja-rim but he discovers that his allowance is running out.
Episode 16
In the school festival, Class 1-3 becomes a customer magnet with their café and picture taking with the most famous students of their class, Kyung-woo and Ja-rim. Byung-hoon, Joo-young and their classmates carries out a hilarious plan to steal Class 1-3's customers and save Class 1-2's face.
Episode 17
After an encounter with middle school acquaintances, Kyung-woo suddenly goes missing for two days. He returns to school but has become hostile to Joo-young. To find out what could have happened to him, Joo-young and the remaining friends talk about Kyung-woo and Joo-young's middle school past.
Episode 18
Kyung-woo realizes he mistakenly thought Joo-young betrayed him by spilling the truth of his long bangs. He reflects on their friendship and apologizes to him.
Episode 19
Ja-rim accidentally sees Joo-young naked. Joo-young becomes embarrassed and stays away from Ja-rim. Kyung-woo starts having feelings for Ja-rim but he goes to hang out with Ye-seul instead.
Episode 20
Class 1-3 remains in last place during exams because of Kyung-woo's low scores owing to his laziness in studying. Kyung-woo's friends and the entire Class 1-3 force him to study in order to save the class' face.
Episode 21
Joo-young, the shortest among their circle of friends, notices Ja-rim's growth spurt and worries she might overtake him. He scrambles to gain height by doing all sorts of exercises and eating height-related foods.
Episode 22
The students of Isam Information High School become hooked to playing milk caps (ttakji) using chicken coupons. Ah-ram gets the hang of it and begins to take the lead. Tasting glory, she challenges Kyung-woo, who has defeated many of his peers, to a match.
Episode 23
Joo-young ponders about having little "skinship" with Ja-rim compared to other couples. Kyung-woo's relationship with Ye-seul is put to the test when they go to a double date with Joo-young and Ja-rim at Lotte World.
Episode 24
The cafeteria is under emergency repairs, so Ja-rim decides to pack lunch for her and Joo-young despite being a lamentable cook. Min-ji goes out with her admirer Sang-hoon, but she learns later on that her crush Kyung-woo has broken up with Ye-seul.
Episode 25
Fearing his mother's wrath, Byung-hoon decides to skip playing games and study for the exams, but his attention is diverted when she meets and gets attracted to a pretty college girl at the library. Ji-soo confesses his feelings to Ah-ram.
Episode 26
Joo-young's grades dropped, prompting his mother to tell him to move out from his apartment and live with his parents once again. His friends decide to hold a send off party for Joo-young.
Episode 27
All Grade 11 students are mandated to retake an exam and Classes 1-2 and 1-3, the last to take the exam, have to stay until nightfall. After the exam, Jin-hee suggests playing an item retrieval game among the friends to test their courage, much to scaredy-cat Kyung-woo's worry.
Episode 28
Joo-young starts receiving text messages from his ex-girlfriend Bo-kyung, unknowing of her ulterior motives. As he gets worried that Ja-rim will know about it and misunderstand him, Joo-young runs into Bo-kyung while he is with Ja-rim. Soon, he notices that Ja-rim is not getting angry with him and has started to treat him nicely.
Episode 29
Kyung-woo reveals to Ja-rim the truth about Bo-kyung. Ja-rim decides to deal with the situation herself and confronts Bo-kyung, much to Joo-young's shock.
Episode 30
Joo-young prepares a secret special event for Ja-rim but things seemingly do not go as he planned.
