Yue Liu Ying was 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. On the wedding night, she planned to poison the bridegroom so that she could escape from the Ling family and regain her freedom. However, 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. 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. Meanwhile, 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. Ling Qi Ye also found that Liu Ying was kind-hearted and talented. The two fell in love eventually and resolved various conspiracies and crises together.