I'm about to talk about World War, and you say it's ancient

Xia Yan, a history major graduate who went to a mountain village to teach, encountered a mudslide and accidentally traveled back more than a thousand years to the Great Zhao Dynasty. With an eye injury, he didn't know where he was! Emperor Zhao Yin of the Great Zhao, Princess Zhao Lingyi, and Prime Minister Zhao Pu discussed getting information about the future development of the Great Zhao from Xia Yan. So they concealed their identities, with Zhao Yin claiming to be the village head and Zhao Pu claiming to be the school principal, and asked Xia Yan to tell stories about the Great Zhao. From Xia Yan's stories, Zhao Yin learned about the "drinking wine to release military power" and used this method to relieve some military generals of their positions. He also learned about the "candlelight and battle-axe shadow" and used this method to kill Zhao Yi, who was planning a rebellion, thus consolidating his rule. During this process, Xia Yan's eye injury gradually improved, and he increasingly noticed something was wrong. After Xia Yan's eye injury fully healed and he learned that he was in the Great Zhao, Zhao Yin betrothed his daughter Zhao Lingyi to Xia Yan to keep him in the court as an official. Seeing that he couldn't return to modern times, Xia Yan temporarily agreed to stay in the Great Zhao and continued to use his future wisdom to consolidate the Great Zhao Dynasty under Zhao Yin's rule!

Synopsis from DramaGo.