In order to avenge her mother, Su Qingyan actively climbs into the bed of her future brother-in-law, Prince Chen Xiao Jinci, at the engagement banquet of her legitimate sister and Prince Chen, becoming a concubine. Step by step, she calculates meticulously, unaware that Xiao Jinci has long loved her to the bone and is willing to be used by her. One stops at nothing for revenge, the other becomes obsessed and mad out of paranoia. This marriage, which began with calculation, turns out to be a premeditated plan spanning ten years.