Bran didn't do anything to Sam. What a joke, if he really attacked Sam right in front of the imperial palace, he would be dead before Sam could die.
As for the matter of Sam kicking his son unconscious, that is another issue, it is his son who made the first move and both of them are equals, Sam only did it in self-defense.
He ordered his attendants who are waiting at the Palace gates to throw his son into the carriage before boarding it.
They left the place and went back to their family grounds. On their way back, Gnyan regained his consciousness, but he didn't even dare to speak when he saw his father's gloomy expression.
After returning to their family, Bran sat Gnyan down and asked.
"What did you do to him?"
"I didn't …"
"Do you think I am stupid? A man who can play you like a fool wouldn't want to deal with you in the first place, you will not be in his circle so why would he bother making enemies with you. Tell me."
