A sudden palace change forced him to take his sister to the country of Yi Ning in the north.
I originally thought that I could get rid of the threat temporarily by coming to the north, but the pursuers sent by the new emperor were still pursuing him.
In order to avoid the pursuers, he accidentally got help from the Crown Prince of Yi Ning by chance.
But the price is to send his sister away from the marriage alliance
(cp is the prince and brother
It's pure fiction, and it's almost all nonsense.
Any similarity is purely coincidental)
Concept: The hero's choice