Sapai Jao

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 Pra-ek's palace. Chai Rong completely ignores Srijittra, so she feels really sad. Instead, she feels more comfortable with the funny M.R. Bodintararajsongpol or Chai Lek.
One day, Srijittra's younger sister, Salin, went to visit her sister at Pra-ek's palace and found Chai Rong and his lover Ying Koy exchanging kisses... Salin then tries to find a way to help her sister get out of the unwanted marriage. There'll be twisted stories that make Salin and Chai Rong become close to each other and finally fall in love.
(Source: Viki)