Monthai (Sean Jindachot) is a young man who has everything. He is the only son of Chao Khun Mahut (Jakkrit Ammarat) and Khun Ying Tubtim (Savitree Samipak). Monthai is in a relationship with Viyada (Kornpassorn Duaysiaklao), the daughter of Vet (Satawat Doongawichit) and Wimon (Nahatai Pichitra). Khun Ying Tubtim wishes for the two to be engaged before Monthai leaves to study abroad.
One day, Pee (Chinaree Anupongpichat), an 8-year-old girl, jumps over the fence into the backyard of the Mahutwet estate. She catches Viyada acting flirtatiously with Monthai and can’t help but laugh. Embarrassed, Viyada tries to hit her, but Monthai stops her and questions Pee kindly. He learns that Pee is an orphan living with her grandmother, Yai Tiam (Sansanee Wattanukul), and had sneaked in to pick Asoke leaves for food. Pitying her, Monthai gives her some pocket money. To Pee, that small amount is a fortune, and Monthai’s kindness is forever etched in her memory as her benefactor.
Chao Khun Mahut is a womanizer with several concubines. One is Nuan (Kwanruedi Glomglom), mother of Nucha (Korakot Tunkaew), and another is Lamom (Nusara Prawanna), who has a daughter from a previous marriage named Lakkhana (Rattanaporn Klinkulabhiran). Fearing Lakkhana might try to seduce Monthai, the Khun Ying constantly watches her. Khun Chian (Prathana Sutchukorn), the head housekeeper and Khun Ying’s close friend, warns Monthai to stay away from Lakkhana, but Monthai views her only as a sister.
Tragedy strikes when Viyada’s car hits and kills Yai Tiam. Vet and Wimon’s family take Pee in, renaming her Piyachat, though she remains a servant in their house. Only Viphawan (Airin Yuktadatta), Viyada’s younger sister, shows her any pity. On the day Monthai leaves for his studies, Pee runs after him to give him a handkerchief embroidered with his name. In return, Monthai picks up an Asoke flower from the ground and gives it to her. Later, Vet is transferred to be the governor of Chiang Mai, forcing Pee to move with them. Meanwhile, the Mahutwet estate falls silent as the relationship between mother and son fractures, leaving Khun Ying Tubtim in tears, mourning her son's absence.
Years Later
Pee (Esther Supreeleela) has grown into a beautiful woman. Monthai completes his studies and sends word to Gua (Jaruwat Cheawaram), his cousin and the Khun Ying’s doctor, that he won't return until he is ready to marry Viyada. However, Viyada has become a wild socialite in Chiang Mai; she has forgotten Monthai and is now targeting Paoliang Pong-in (Natt Devahastin na Ayudhya).
Unaware of this, Monthai continues to write love letters to Viyada. In reality, it is Pee who replies to his letters and sends him hand-knitted scarves and sweaters in Viyada’s name.
Viyada relentlessly pursues Pong-in, but he remains indifferent because his heart belongs to his ex-lover, Maenwad (Ratklao Chaichuenjit). Pong-in is close to Pee, as she understands his feelings for Maenwad. Jealous of Pong-in's attention toward Pee, Viyada looks for a way to get rid of her. When Khun Chian writes to ask Viyada to care for the ailing Khun Ying Tubtim, Viphawan suggests sending Pee in Viyada's place. Wimon agrees, wanting to spare her daughter the trouble, and Pee returns to the Mahutwet estate.
The Return
The Khun Ying, unable to recognize Pee, calls her "Viyada." To protect the Khun Ying’s health, Khun Chian asks Pee to play along. Pee agrees out of compassion and cares for her diligently. Gua also mistakenly believes Pee is Viyada and informs Monthai that his fiancée is taking wonderful care of his mother. Deeply touched, Monthai decides to return to Thailand immediately to find his "perfect" woman.
Upon his arrival, Monthai is furious to find Pee there. He accuses her of impersonating Viyada. Even when Khun Chian explains that it was the Khun Ying’s misunderstanding and that Pee came because Viyada refused, Monthai refuses to believe it. The Khun Ying is overjoyed at his return and pushes for an immediate marriage between Monthai and "Viyada." This only fuels Monthai’s suspicion that Pee is an opportunist trying to marry into his family.
How will the love story of Pee and Monthai end?