Yun Yan, a student of modern history, traveled through time when he touched a bronze sword from the Tang Dynasty in a museum and became the young master of the "Yun Family Martial Arts School" on the outskirts of Chang'an. At this time, the martial arts school was suppressed for refusing to adhere to the "Black Iron Alliance", and his father was seriously injured and fell into coma. In order to save his father and survive, Yun Yan relied on modern fighting knowledge to improve his family's swordsmanship, and unexpectedly awakened his weak inner breath. He sneaked into Chang'an to search for healing medicinal materials, but was involved in the "Qingyi Pavilion" plot to assassinate Zhang Jiuling, and accidentally saved the villain leader Su Lie. In order to find out the truth about time travel and clues to the fragments of "The General Essentials of the Military Classics", Yun Yan faced the pursuit of Jianghu sects, while using historical knowledge to remind Zhang Jiuling to guard against Li Linfu's trap. In the Battle of Hexi, he used the "Bu-tank coordination" idea to help the Tang army defeat the Tibetan sneak attack, and gradually grew from an ignorant boy to a knight who could balance the court and the Jianghu.
