Go Hee-soo is the granddaughter of the president of South Korea’s biggest conglomerate KS Group. Raised by her grandfather, she is charming and elegant. However, she regrets that she lost her mother, who died in a plane accident with Kim Chan-ho’s parents. One day she meets Kang Woo-jin who just came back from the United Kingdom. She is attracted by his carefree personality as he shows her a world she never knew. But Chan-ho, a very good friend of Kang Woo-jin’s, grew up with Hee-soo and never regarded her as his older sister. Their love triangle is just the beginning.