Once Upon A Time is a disappointing adaptation of To The Sky Kingdom by Tang Qi and in no way compares to the book or the masterfully presented internet/tv series entitled "Eternal Love" starring Mark Chao and Yang Mi. This movie, is at best, a rushed summation of the book with many of the essential elements and important characters missing or IMO, misrepresented. I suggest that you watch the series on Netflix or You Tube to grasp the magnitude of this great love story.