Xiong Xi Ruo (Xi Zi) is a young female painter who infiltrates the family home of the powerful Li family to paint a copy of a precious item. However, her escape from the Li home goes horribly wrong and she finds her fate at the mercy of Li family heir Li Hong Bin (Xia Ning Jin). On the verge of arrest, Li Hong Bin and Xiong Xi Ruo hatch a lie – they pretend that she is pregnant with his child. This arrangement suits Li Hong Bin fine, as a marriage with Xiong Xi Ruo will help him escape an arranged marriage with the daughter of the Song family – a union he is particularly keen to avoid. The Li family grants its consent for Li Hong Bin and Xiong Xi Ruo to get married, but it is not long before some relatives – and the plotting Song family – begin to suspect that the pregnancy is a fake. Meanwhile, as Li Hong Bin and Xiong Xi Ruo spend more time in each other's company, they begin to develop a growing fondness for one another. Could love bloom between the pair? And can they survive – or even thwart – the schemes at court? This drama was based on a long-running web-based cartoon series named “Unreliable Princess.” “Oh! My Sweet Liar!” is a 2020 Chinese period drama series that was directed by Cheng Ming Ko.