Anna Leonowens (Jodie Foster), a British widow, arrives in Siam with her son Louis (Tom Felton) to educate the King Mongkut’s (Yun-Fat Chow) many children. With her strong will, intelligence, and benevolence, she quickly earns the King's respect. Mongkut aims to modernize Siam, hopeful that this will aid in resisting colonial threats while preserving its rich traditions. Throughout their interactions, the two engage in discussions about love, culture, and the stark differences between Western and Eastern perspectives. Notably, Mongkut brushes aside the idea that one man could ever be satisfied with a single wife.
To curry favor with British ambassadors, the King organizes an extravagant reception and entrusts Anna with its planning. During the event, an engaging exchange unfolds between Mongkut and Sir Mycroft Kincaid (Bill Stewart) of the East India Company, where Westerners express their misconceptions about Siam being a superstitious and outdated nation. In a poignant moment, the King shares a dance with Anna, further deepening their connection.
Anna finds joy in the playful spirit of the royal children, especially young Princess Fa-Ying (Melissa Campbell), who has a special fondness for the monkeys that inhabit the royal garden. Tragedy strikes when Fa-Ying falls ill with cholera, leading to a heartbreaking farewell. Anna arrives just in time to witness the final moments of the Princess, as Mongkut cradles her in sorrow. The King later discovers that one of the monkeys has playfully taken his glasses, reminiscent of Fa-Ying’s love for them. In this time of grief, Mongkut finds solace in his belief in reincarnation, cherishing the hope that Fa-Ying may return as one of her beloved pets.
Lady Tuptim (Bai Ling), the King's newest concubine, struggles with her own heartache, having been brought to the court against her will while still secretly belonging to another man, Khun Phra Balat (Sean Ghazi). Yearning for her true love, she disguises herself as a man and attempts to escape, only to be caught and brought back, facing severe consequences for her disobedience. Anna, witnessing Tuptim's punishment, finds the situation unbearable and intervenes, though her actions inadvertently complicate matters for Mongkut, who cannot show leniency without appearing beholden to her. This leads to a tragic execution of Tuptim and Balat.
As turmoil brews, Siam faces a grave threat from what seems to be a British-backed coup, led by General Alak (Randall Duk Kim) and his collaborator, who brings a battalion of Burmese soldiers. In a twist of fate, Alak betrays Mongkut, resulting in the death of Prince Chaofa (Kay Siu Lim), which sets the stage for revenge. Preparing for an invasion, Alak seeks to eliminate Mongkut and his progeny.
Mongkut cleverly orchestrates a ruse, claiming that a white elephant has been sighted, prompting a court journey that allows him time to escape with his family and prepare for confrontation. Anna, aware of the subterfuge, joins the royal family, lending credence to the tale of the white elephant. However, they soon find themselves cornered by Alak’s forces. In a bold move, Mongkut and his soldiers set explosives on a precarious bridge to thwart the impending attack.
Meanwhile, Anna and Louis devise a clever stratagem from their concealed location in the forest, using sound and fireworks to create a feigned military presence, inciting panic among Alak’s soldiers. Following the chaotic retreat of the Burmese troops, Mongkut encounters Alak, who stands isolated and desperate. Refusing to take Alak's life, Mongkut chooses to uphold his honor, but the confrontation ends with a dramatic explosion as the guard detonates the bridge, obliterating Alak in the process.
In a touching conclusion, Mongkut and Anna share a final dance, marking the bittersweet nature of their farewell. He reveals that he finally understands the potential for a man's happiness in being devoted to just one woman. The story closes with a reflective note about Chulalongkorn’s ascension to the throne, recognizing his father's vision that led to the abolition of slavery and the promotion of religious freedom in Siam.
