Krystal Jung is a 17 year old girl, but she's a very special girl. Even she has just her father, her life was always bright and normal. Jung has also a brother, called Eunhyuk. Eunhyuk is a warm-harted brother.

Krystal is really close to her best friend Minho, and they spend much time together.

However, with the passage of time, Eunhyuk, her brother will going to have a lot of problems, because the alcohol addicts; and one day, Minho left Korea and will study abroad. Then, Krystal feels like she possibly could like her BFF... With his departure, Krystal become a problematic student girl and nobody can make her return to the old Krystal.