Xuanwumen Starry Sky

In the ninth year of Wude, there were two power centers hanging over Chang'an City at the same time - one in the East Palace of Taiji Palace and the other in Tiance Palace. The officials of the empire looked up at the sky every day, wondering which sun would fall first. Decades later, sixty-year-old Li Shimin often dreamed of his brother. He was reflecting on whether the Xuanwumen incident that year could have been avoided? Why should this happen between brothers? What should his children and grandchildren do?