Native title: สายธารหัวใจ
English title: Sai Tarn Hua Jai
Narang was adopted into Thun Chai Mamthep’s family but was treated like a servant because of his poor background. He fell in love with Pathawee, Thun Chai’s daughter, who used him to get back at her father for not treating her mother well and marrying Prakong, a servant. Prakong and Lamoon, her daughter, were both ignored by Thun Chai, who’s an alcoholic and a playboy. When Thun Chai finds out about Narangand Pathawee’s relationship, Narang is forced to go study overseas.
Years later, he comes back to help Thun Chai with his hotel business that is about to go bankrupt. He suggests selling some of the hotel’s shares to Sunanta, a businesswoman. He then meets Siriganya, Sunanta’s secretary, but misunderstandings cause them to not like each other at first. Eventually, they fall in love, but Pathawee is still possessive of Narang and she’s not willing to let him go.