Yue Liu Ying was just a simple and playful girl before she was forced by her foster brother into marrying Ling Qi Ye in order to spy on him. She didn't want to be a spy, but couldn't get rid of the control of her foster brother, so she had to find another way to live. On the wedding night, she planned to poison the bridegroom to make it look like a fake death so that she could escape from the Ling family and regain her freedom. However, on the day of the wedding, she and Ling Qi Ye both had their own incentives for the marriage and end up becoming a "Mr. and Mrs. Smith" in ancient times. However, the innocent Yue Liu Ying couldn't outmaneuver Ling Qi Ye so she has no choice but to temporarily let go of the idea of running away and wait for another chance in the future. In the meantime, Yue Liu Ying gradually found out that Ling Qi Ye was not as despicable as her foster brother described, but was a good man who was devoted, thoughtful, and responsible, while Ling Qiye also found that Liu Ying was kind-hearted and talented. The two fell in love eventually and resolved various conspiracies and crises together.