When Hai Zhong went back and found out his uncle had been promoting the deaths if him and his brother in order to get the throne, he was disappointed but not surprised.
He had always known that hus uncle thought it was unfair for his father to be the ruler and those thoughts only magnified when he started rulling.
He once believed that even if his uncle had those thoughts in his heart, he wouldn't dare to act on it but it seems he underestimated his greed.
The king and prince came back safely and Veyrin was exposed for colluding with both sirens and humans so he was thrown in the dungeon.
Hai Zhong was on his way to visit this uncle of his.