Jun Jihyun(you) never get noticed by her classmates and teachers.She just want to end her highschool life and go to the college and start a new life. But one day she met the most popular boy in her school, Mark Tuan and her life has totally changed.  

Sunmi's mother has decided to remarry. Sunmi suddenly has to live with three handsome brothers, JB, Mark, and Jinyoung. She wanted to have a happy family, but the house has become a dangerous animal zone. Fighting dangerous situations everyday…