Choi Junhong is 16 and enjoys his high school-live as womanizer. One day his 5- years old cousin Tae Joon is left by the Choi- family from his mother. And  Junhong of all should take care of him! Tae Joon´s cute nature is heartbreaking, but can he win the heart of the cool Junhong, who is his "new brother"?

Characters:

- Choi Junhong

- 16 years old

- known as Zelo

- womanizer

- cheerful, cheeky, dumb and carefree

- taking care of Tae Joon

- changed into a caring person

- love interest is Song Ji Hye

- Choi Tae Joon

- 5 years old

- his mother left him

- his father died

- cheerful, sweet, curious

- love his "new brother" Zelo

- Song Ji Hye

- 16 years old

- her father died when she was 6

- living alone

- cold-hearted and uncaring towards people she doesn´t like

- to friends caring, calm and kind

- love interest is Zelo