What role does Qian Liuyin play in a time-travel play? I have seen it before, but I know the general plot, but I don't know the name. Please help me!

I don't know if there is a Qian Liuyin, but I have seen the movie you mentioned, Time and Space Rescue starring Wallace Huo and Jing Tian.

Otaku Erdan (Wallace Huo) dreamed of becoming a great writer and creating a historical biography, but he was ridiculed by the publisher (Lin Xue) and suffered repeated defeats. On the night of a meteor shower, Er Dan returned to the prosperous Tang Dynasty with the help of a family heirloom, and saved his idol Shi () by mistake, and fell in love with his sister, the quaint little princess Ganoderma lucidum (). In order to help Shi defeat the enemies with ulterior motives, Erdan took Shi's brothers and sisters back and forth between ancient times and modern times, turning Gan Kun upside down and killing him in all directions, which led to a series of hilarious stories. Just as Er Dan and Xiao Jun returned to modern times and looked forward to a happy new life, they found that everything was not as simple as they thought, and a big conspiracy was waiting for them to defeat. ...

Note: The bad guy you are talking about is either history.