In the winter of 755, An Lushan captured Luoyang, his army's advance threatening Chang'an. The famed generals Gao Xianzhi and Feng Changqing retreated to Tong Pass, where the supervising eunuch Bian Lingcheng had them executed before the troops on charges of “breaking discipline and losing the army.” In this moment of crisis, Geshu Han was given command and led fifty thousand battered soldiers to defend the Tang Empire's last gateway.
That's what the history books say.
What the history books don't say is that in Tong Pass there was a laborer assigned to the supply corps. His name was Chen Shu, and he came from the year 2024, thirteen hundred years in the future. He remembers that Luoyang will fall, that Tong Pass will hold, that Geshu Han will be defeated, that Chang'an will be taken, and that a woman will be hanged beneath a pear tree at Mawei Station.
But he can't change a thing.
Still, he knows: on the first day of the first lunar month, at Tong Pass.
That day, he has to stand at the East Gate.
