Strain of Blood.

Krai comes from a family of soldiers and has spent most of his life fighting in battles and wars for his country. Dao is the youngest daughter of a prominent village chief, who is very curious and happy go lucky as a youngster. Krai's older brother marries Dao's older sister, sealing the connection between both families. Krai meets Dao as a young girl and he spends a lot of time taking care of her, buying her toys and taking her on village outings with him to the market. Krai and his older brother are called away to defend the border and he promises Dao that he will return to take care of her always as an older brother. Years later, Krai comes back to realize that Dao has grown into a young beautiful maiden and the good feelings that both had for each other from years ago resurface into true love.