The young lady is not the real one.

The female lead, Si Nian, is forcibly kept by the male lead, Fu Jingyan, because she resembles Fu Jingyan's elder sister in appearance. Si Nian pretends to be stupid only to use Fu Jingyan to take revenge on the Shen family. The two are entangled with each other with ulterior motives. In the end, they become each other's salvation and fall in love with each other...