Ask for the name of a Hong Kong costume TV series.

There are two plots very similar to what you said. One is "The Son of Heaven Seeks the Dragon", and Chen Musheng is Li Longji, an exiled folk, who was counted as the emperor's life and finally returned to the Tang Dynasty. The other is "secret calculation", in which Chen Musheng is also counted as a descendant of the royal family in the later Zhou Dynasty. Both are fine. I suggest you have a look.