Eun Ha Won (Park So-dam) is a bright college student who dreams of becoming a teacher. Unfortunately, she loses her mother in a tragic accident, moves in with a cruel stepmother, and has no money for her education. One day, she helps an old man and as fate would have it, moves into a gorgeous mansion with three equally gorgeous men, who also happen to be billionaire cousins and heirs to the Kang family fortune. Between the rebel-minded loner Kang Ji Woon (Jung Il-woo), playboy money machine Kang Hyun Min (Ahn Jae-hyun) and the super-sweet singer Kang Seo Woo (Lee Jung-shin), Eun Ha Won finds herself in the middle of the hottest love quadrangle to ever befall a modern fairy tale princess. Rounding out the mansion’s chaebol lifestyle are Lee Yoon Sung (Choi Min), who serves as the cousins’ handsome bodyguard, and Park Hye Ji (Son Na-eun), a gorgeous girl who has her own interests in the Kang family and is not above manipulating one cousin to get closer to another.