Voyage of Haihun

It tells the story of a frustrated modern man named Wang Heng who accidentally came to the Western Han Dynasty and met a female knight named De Jiu, who looked like his ex-girlfriend in real life. With the memory of reality, Wang Heng met the cheerful prince Liu He. The two became close friends after going through misunderstandings and challenges. He and De Jiu became colleagues. They tried to challenge history and change their fate but fell into the abyss because of their own obsession and cowardice. Brothers in distress faced their own failures and grew together. People who fought side by side healed each other.

(Source: Chinese = Baidu || Translation = MyDramaList)