"Dark meets Dark." Krystal was forced to transfer into a different school after bad behaviors from her other school. She had no friends, people were afraid of her because of her cold aura and attitude. Kai is the kingka to Gyeongi High School. He is a cold person, with 11 best friends who are by his side. Both of them weren't like that from the start. They used to be a cheerful child, but things change as time pass by. Will these two fall in love? Will they be able to break each other's walls and find each other's cheerful self again?