Yaya meets herself from 20 years later.
Twenty years later, aliens stole and tampered with the earth's historical and cultural treasures through time travel. In the future, Yaya becomes a guardian of history and a thorn in the side of aliens.
Dayaya travels back to 20 years ago, on the one hand to protect Xiao Yaya from aliens, and on the other hand she can fight side by side with Xiao Yaya to save the stolen history.
Xiao Yaya got a magical bookmark, which can take her across China for five thousand years.
Purpose: Learn history, learn science, know how to be grateful, and cherish the present