To cope with his family's pressure to marry, Ling Yu paid someone to enter a fake marriage. When registering the marriage certificate, he was told he was already registered, and his wife was Shen Youchu, the head of the Shen family whom he had never met. He is actually the true young master of the Ling family, whose identity was switched in childhood, living alone outside under the guise of an illegitimate son. Because Shen Youchu's grandmother suffers from Alzheimer's disease and mistook him for her grandson-in-law, the two were forced into a binding relationship. From initial probing, suspicion, and numerous misunderstandings, to facing family scheming and workplace turmoil together, they uncover the buried truth of the switched identities. The fake marriage gradually turns into true affection, and the two walk side by side, reaping warmth and belonging for each other in the ordinary world of mortals.