Synopsis - 

Minho is a very fun and happy person, before. After, his parents died because of car accident. He become a very cold and hot tempered person. He lived alone with his sister, Ha Na. Appearance of YooNa makes his life changed. Ha Na likes YooNa very much. She would like YooNa to be her sister.

Character - 

Yoona - She's a very fun and happy person. At first, she thought Ha Na was annoying. But, she realised that Ha Na is cute and adorable. 

Choi Minho - He's a cold and hot tempered person. But, he can do anything for his sister. ANYTHING. That was his promised with his mom.

Ha Na - Adorable and Cute kid. She likes YooNa very much. She want YooNa to be her sister.