Couples: 

JongYu (JonghyunXJinki)

TaeKey (TaeminxKeybum)

Characters:

Lee Jinki: 

-new kid

-3rd year at high school

-not very popular

-quiet

-VERY smart and talented at singing

Kim Jonghyun

-very popular

-3rd year in high school

-good at singing

-not very smart

-can be a big jerk, but is just trying to cover up his tender heart

Kim Kibum

-diva

-3rd year in high school

-doesnt bother with the popular kids

-gets decent grades

-wants to start a dance team

-very nice to his friends and very friendly with new people, but couldn't care less about mean people

Lee Taemin

-1st year high school

-very good at dancing

-reads a lot

-shy and quiet, but very fun when he's with friends

Sub-Characters:

Kim Sunggyu

-Jonghyun's friend

-also a jerk

-3rd year in high school

Lee Sungjong

-diva

-1st year in high school

-very friendly only to people who are nice to him