Librarian Su Xinyi was forced to marry Fu Yanzhou, the president of Fu Group, because her sister Su Tang escaped from marriage. She originally thought it was a contract marriage where everyone gets what they need, but as they get along day and night, they gradually discover that the man who is rumored to be "cold-blooded and ruthless" hides a defensive shell built up due to childhood trauma; and she uses the delicacy and tenacity soaked in the library to slowly melt his ice wall. In the process, the younger sister's calculations, the emergence of old family grudges, and the traps of business rivals are layered one after another. The two go from testing each other to fighting side by side. In the end, in the process of healing each other, they realize that "marriage by mistake" is the most correct arrangement of fate.
