Gun and Golf have been pen pals ever since the fifth grade, and now that they are both in high school, they still maintain the habit of writing letters to each other. One day, the two, who have never actually met in person, decide to take a leap and meet one another for the first time at the school's annual sports meet.

After communicating over letters for the longest time, Gun and Golf finally decide to put down their pens and papers and resort to the miracles of the internet, thereby beginning their online journey over MSN Messenger. Meanwhile, the messaging app is also helping shorten the distance between Em and Name, thereby bringing the two closer together.

With the university application results approaching soon, it seems that this group of best friends who have been inseparable ever since their childhood are finally bound to go their separate ways and pursue their individual dreams.

On the day of the university registration, Gun and Golf meet each other as classmates in the same school and same faculty. But will the two be able to find out that they have already written letters to each other before?

As Gun hesitates to let Golf know that he is in fact "Classmate No. 8," Em and Name, who haven't spoken to each other for quite some time, begin to feel increasingly distant from one another.

As Gun and Golf make their way to the stationery store, they have an intimate exchange that neither of them saw coming, Meanwhile, Nucknan finally musters up the courage to meet the girl he's been talking to for a while now.

As Name spends his time thinking about Em, he comes across a new friend on MSN that he takes a liking to; meanwhile, Gun discovers that Golf has been secretly texting and talking to a girl online, which has him feeling concerned.

Upon visiting Gun's room, Golf comes across some sketches that immediately reminds him of his memories from the past. In the meantime, Em and Name finally decide to talk over the phone to clear up a misunderstanding concerning one of their online conversations.

Em really helps out Name's mother while she's hospitalized, and the two of them reunite and make up; Golf invites Gun to go back to meet his parents, but what will his parents say to Gun?

Nucknan tries his best to find the girl with whom he lost contact with for ages; everyone finally graduates from university and begins preparing for a new life.

One day, Em invites Name to complete a special mission together; at the same time, Gun also prepares a surprise for Golf.

Gun and Golf's relationship runs into troubles, so Gun decides to break up, and the two must make a difficult decision.

As Gun and Golf were about to say their goodbyes, Golf suddenly gives a surprise; everyone returns to their hometowns and shares their respective good news.

Champ's sister holds a wedding banquet, and as a result Champ re-examines the relationship with his family; Em finally expresses how he feels to the person he likes.