I translated some brief of the novel that I found on someone's blog
When King of Panjarat passed away in sudden and his queen was grieved and died after him, Janthrapa Dinasty had only pretty Princess Sisira (Aff) and Prince Tharathep, a young crown prince left. So, it caused Konjanat, the bureaucrat, seized their throne and succeed himself as the ruler. He forced Princess Sisira to marry Theekayu (Aum), his own nephew, so that his Yaowarajee clan could be the ruler.
Princess Sisira had to unwillingly marry Theekayu for her brother's safety, but she had a wish to seize the throne back and chased Yaowarajee clan out of the land in the future.
Theekayu was Konjanat's nephew. His appearance was like a playboy guy and stayed in the brothel all day. Everyone thought that since he was raised up under the care of that cunning bureaucrat, he might have the same attitude as his uncle.
I'll go hunting for the novel to read.