The story begins in the dense Borneo Jungle in 1816, where British soldiers have invaded and set fire to the homes of the native tribes. The tribe leader, standing proudly before his tribe, bids a tearful farewell to his young son and wife as he leads a group of warriors to confront the enemy.
Twenty-five years later, Marianne, the adventurous daughter of the English consul, dashes through the jungle, collecting exotic animals, including spiders. A fierce tiger appears, ready to attack, but her trusty aide, Sergeant Murray, saves the day with a swift gunshot.
Meanwhile, in the vast seas, Captain Yanez De Gamora pretends to be a shipwrecked survivor and is rescued by the Sultan's men. The rescuers intend to enslave them, but a group of other pirates emerges from beneath the waves and takes over the ship. A fierce battle ensues, and the Sultan's men are tossed overboard. The pirates rescue a man from the Dayak tribe named Lamai, who alerts them to the presence of British soldiers on board. Just in time, they launch an ambush and force the soldiers to surrender.
After searching the ship, the pirates find nothing valuable but stones. Lamai explains that these stones are "cursed" and have made the Sultan enslave his tribespeople in his mines. Although the metal looks worthless, the pirate captain, Sandokan, believes it must be worth something if the British need it. Sandokan decides to head to Labuan Island, home to the English Consulate, to find out more about these mysterious stones.
On the island, Marianne returns home from her jungle adventures and finds a suitor waiting for her - Sir William. Frances, her mother, insists on their marriage even though Marianne opposes it. Frances convinces Sir William that Marianne is a proper lady. In an act of rebellion, Marianne meets Sir William barefoot and has her maid bring out a spider instead of tea. Sir William is terrified and refuses the marriage arrangement.
Marianne finds her father, Anthony, protesting against returning to London. Just then, Sergeant Murray interrupts their conversation with news of the attack on Sultan's ship. Marianne rushes to the infirmary to help attend to the wounded soldiers.
Meanwhile, Sandokan and his crew conducted the final rites for their fallen comrades aboard their ship as Lamai sang a native song to ease their souls into peace. Later, Lamai recounted his mission to Sandokan—to rescue his tribespeople, whom he believed Sandokan to be, a great warrior with the spirit of a tiger, akin to the prophesied savior of his native tribe. Sandokan chuckled off the tale, insisting that the only missions he undertook were those with tangible rewards.
To address the rampant piracy, Anthony hired the renowned pirate hunter, James Brook. Brook and his men sank Sandokan's boat as he was headed to the island with Lamai and captured all his crew members. At the same time, Anthony insisted that Marianne return to London as the island was no longer safe with pirates lurking around.
Marianne stormed out of the house and headed to the beach, where she found Sandokan. She helped him back to the infirmary and nursed him back to health. Realizing that he was surrounded by the British, Sandokan spun a lie, claiming to be a merchant named Ismail whose ship had been attacked by pirates.
When Marianne took Ismail to see her father, they ran into the Sultan of Brunei. He was there to argue with Anthony about the lost goods, demanding that Anthony bring Her Majesty's fleet for stronger protection or he would approach the Dutch, who were also interested in his cursed stones.
Anthony questioned Sandokan about the attack, and he claimed to have been thrown overboard, thus having no valuable information to offer. He also lied about transporting silk, taking the opportunity to learn more about the cursed stones in the process.
Anthony explains that it can be utilized in crafting intricate components for industrial machinery, motors, and even bullets. Agreeing to host Sandokan until Marianne's ship to London arrives, Anthony witnesses a heartwarming moment as Sandokan and Marianne rescue Lamai during a beach ride. Marianne notices Lamai's tattoo, similar to that of her maid, Sani, and brings her to the infirmary to assist in his care. Unfortunately, Lamai's injuries are too severe for recovery, deepening Marianne's disdain for pirates.
Brooke brings the captured pirates to the island and confines them in the prison, convinced that he sank Sandokan's boat, believing him dead. When Marianne enquires about the pirates' fate, she is saddened to learn that they will be hanged after her birthday party. She requests a meeting with the pirates to understand their motivations. Meanwhile, a British soldier who recognizes Sandokan suddenly dies in the infirmary. Brooke requests Sandokan to identify the attackers who sank his ship, secretly handing Yanez a knife under the guise of seeking revenge.
Marianne expresses concern for the youngest pirate, almost her age. Sandokan advises her to ask Anthony for a pardon. Later, at a dinner hosted in Brooke's honor, Anthony announces that they will hunt for the island's tiger the next day, with Brooke insisting on inviting the merchant, Ismail. During the hunt, Brooke gives Sandokan a broken gun. When the tiger attacks Marianne, Sandokan is forced to use a knife to save her, stabbing the tiger but failing to kill it. Brooke arrives in time to shoot and kill the tiger, leading Marianne back to the consulate.
Sani learns of her parents' death and her brother's enslavement in the mines through Lamai's revelations. Before his death, Lamai asks Sani to rescue their tribespeople and seek Sandokan's help. It becomes apparent that Brooke is ambitious and desires to become the next English Consul, proposing marriage to Marianne on her birthday as a means to gain power. Although initially skeptical, Marianne is not entirely opposed to the idea.
Meanwhile, Sandokan teams up with Sani to assist his crew in escaping after the birthday party, promising to help her rescue her brother. Sani gets all the soldiers drunk, allowing Sandokan to sneak into the prison and rescue them. The plan progresses smoothly until they unexpectedly encounter Marianne. Sandokan is forced to abduct her as Brooke receives news that Ismail is the pirate captain but is too late. Sandokan and his crew leave the island with Marianne as their hostage.
