A civil engineering prodigy from the 21st century accidentally transmigrates to the Jiading era of the Southern Song, in the early 13th century, when Song, Jin, and Mongol forces are locked in a struggle for power. He becomes the son of a disgraced official, exiled for offending a superior to the remote, dilapidated border fortress of Yunchuan. From the start, all he has is a crumbling city wall and a few dozen soldiers and civilians, gaunt with hunger. Starting from nothing, Lu Mingyuan applies modern knowledge and technology to turn a derelict border town into a formidable fortress and thriving commercial hub. At last, caught between the Song, Jin, and Mongol powers, he builds a force of his own and changes the course of history.
