Majurat See Nam Pueng

The Setup and The Switch Madame Rumpa, the head of a wealthy Bangkok family, has two daughters: Rochana-Chai (the elder) and Rom-Ruethai (the younger). Madame Rumpa has a pact with her friend from Sukhothai, Madame Prem Pattamakul, to marry their children. However, Rom-Ruethai, the biological daughter, is disgusted by the idea of an arranged marriage ("Klum Thung Chon") to a man she assumes is a country bumpkin. She refuses to marry Pat Pattamakul. To get out of it, she cruelly reveals to Rochana-Chai that she is actually adopted and forces her to take her place in the marriage to repay the family's kindness. Rochana-Chai, who already has a boyfriend named Prawut, is heartbroken but agrees to the engagement out of gratitude.
The Wedding and Regret When Madame Prem and Pat arrive in Bangkok, the truth comes out. Pat is furious that Madame Rumpa is trying to switch brides, seeing it as a scam to get his money, but he agrees to go through with the wedding anyway. Meanwhile, when Rom-Ruethai sees that Pat is actually incredibly handsome and wealthy, she immediately regrets her decision and tries to seduce him, but Pat ignores her.
Life in Sukhothai Pat takes Rochana-Chai back to his home in Sukhothai. Their marriage is in name only. Pat, still angry about the deception, constantly bullies and insults her. Complications arise when Urarat, a woman obsessed with Pat, interferes. Meanwhile, Pat’s friends—Poonthawee (a wealthy landowner) and Palad Warah (a deputy district officer)—meet Rochana-Chai. Thinking she is Pat’s sister, they both fall in love with her. Even after Poonthawee learns she is Pat’s wife, he struggles to suppress his feelings.
The Climax Pat tries to force a divorce, while Urarat plays the "third hand" to break them up. The breaking point comes when Urarat lies to Rochana-Chai, claiming she is pregnant with Pat’s child. Devastated, Rochana-Chai flees the house. She is taken in by Poonthawee (staying with his housekeeper to avoid scandal), while Poonthawee confronts Palad Warah to find the truth. It is revealed that the baby actually belongs to Warah.
The Resolution Pat frantically searches for his wife. He finds her at Poonthawee's house, leading to a brief misunderstanding, but they eventually reconcile. Rochana-Chai forgives him, and they finally understand their true love for one another.
The Subplot Ending Back in Bangkok, Rom-Ruethai and Prawut (Rochana-Chai's ex-boyfriend) are both bitter. Prawut still wants Rochana-Chai, and Rom-Ruethai still wants Pat. In a moment of drunkenness and recklessness, they sleep together despite not loving each other. Realizing they have both lost the people they truly wanted (who are now happily together), they return to Bangkok and decide to marry each other, hoping to fill the void in their hearts.