M.R. Kittirajnarin, or Chai Rong, aka Khunchai Rong, was supposed to get into an arranged marriage with Srijittra, the older daughter of the Rachadamri family. He hesitated because he's already been in love with Ying Koy, aka Khunying Koy, but his family refused to let him marry a divorced woman.
Srijittra is an obedient daughter, so she agrees easily and prepares to be a royal in-law by learning manners and stuff at