He is Gu Chenzhou, the cold and distinguished heir to a wealthy family. She is Shen Zhiyi, a woman who carefully plans her every move. A chance encounter turns her into a substitute for the woman he has always cherished. He gives her a contract, stipulating that she can only play the role of that woman, but forgets to remind himself of one thing: a substitute is the easiest to fall in love, while a contract is the hardest thing to keep one's heart out of. When the real woman returns, Gu Chenzhou discovers that the woman he treated as a replacement has already become the one person he cannot bear to lose.