During the war in the Heng Dynasty, princess Ji Yunyang summoned the so-called "nation's saviour" at the cost of her life. As a result, the soul of Zhang Fang, an ordinary female college student from the 21st century ended up in the princess' body. The only way for her to return back to her original world is to fulfil the original princess' will-- finding the world sword and restoring her country Hengguo. Thus begins the forced journey of 21st century Ji Yunyang, maid Xiaoqin, and guard Wu Fei to locate the "sword of the world".