One day, she meets an old man who convinces her to move 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), 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's been neighbors/in love with Hyun-Min since childhood.