First day of school

Hyoyeon - has two rule here
she played the rule as herself and also as her younger sister.

Kai - his rule here is a little bit bad boy.

Kyungsoo - Kai's best friend and Sunny's boyfriend.

Sunny - Hyoyeon's one and only. best friend, a trusted and caring, she is also Kyungsoo's girlfriend.

Lay - Hyoyeon's Knight and shining armor.

Hyonnies - Hyoyeon's second rule and her twin dongsaeng

Yuri - Lay's ex-girlfriend (cameo)

Suzy - Kai's cousin (cameo)