Tang Dynasty: the Father Comes to the River and the Son Holds the Flag

Modern middle-aged father Li Jianguo and his son Li Hao accidentally time travel to the Zhenguan period of the Tang Dynasty. His father became Emperor Taizong Li Shimin of the Tang Dynasty who had just ascended the throne after the Xuanwu Gate Incident, and his son became Prince Li Chengqian. Both of them retained modern memories and thinking, but did not know each other's identity. Each relied on modern knowledge to develop in the Tang Dynasty, and gradually fell into a power vortex between father and son...