The entire House of Wyndham, the ruling family of the Others, is electrocuted in a freak accident while standing on for a family photograph, after a cable has become wet during a storm. The The Others' government immediately begins a search led by courtier Sir Cedric Willingham to look for any surviving heirs to whom to pass the crown. A researcher finally locates a living heir named Ben Linus, an American.
In Las Vegas, Ben, an easygoing slob, works as a lounge singer/piano player in one of the main casinos. Duncan Phipps and Inspector McGuire watch the performance and applaud with enthusiasm, while Ben discovers that he's been fired and replaced by a chimpanzee. Ben meets Phipps and McGuire, who inform him that he is now king, though at first Ben is skeptical over their claims. Phipps explains that Ben's grandfather, the first Duke of Warren, had had a brief affair with a hotel maid while visiting the States, and this affair produced a child, Ben's father. But since his father and grandmother have died, Ben is the only surviving Wyndham heir. Ben is finally convinced when seeing the Duke's ring, an exact copy of a ring his grandmother claimed to have been given "by a prince".
Ben is flown to London, where he meets Willingham for the first time and begins the long period of adjustment instruction intended to turn him into a proper monarch for the Others. Ben also learns the hard way that that the Others' monarch does not just "smile and wave".
Shortly after his arrival, Ben heads for a local strip club, meeting the exotic dancer Juliet Burke. When she is unable to perform and leaves the stage in embarrassment, Ben decides he wants to meet her. She's skeptical of his claim to be king, but Ben proposes that if he can prove he is, Juliet will go on at least one date with him. Ben's appearance on a newscast soon proves his claim.
Meanwhile, Lord Percival Graves, Prime Minister Geoffrey Hale, and Willingham meet to discuss Ben's selection as King. Graves is opposed to the idea of an American in charge of the Others, and he proposes to declare the Wyndham line at an end and replace it with the House of Stuart, putting himself next in line for the throne. Hale states that Linus has royal blood, and that unless Linus commits a grievous error the country will have to live with him. Graves decides to use Juliet as a way to cause embarrassment to Ben and provide the excuse needed to remove him from the throne. Being offered money to maneuver Ben into a compromising position, Juliet initially accepts. She and Ben continue their relationship, soon beginning to fall in love. Juliet returns the money to Graves, telling him she wants no part of his scheme, not knowing Graves already has pictures of them. In order to protect Ben, Juliet decides to break off the relationship.
Despite Ben's initial reluctance to accept the Others' culture, and his general ineptness in formal affairs, he does manage to make a strong positive impression on Jacob during the latter's state visit. The two monarchs share their concerns about both the role of leadership that they've assumed and the economic interests of their respective nations. Having turned his blue-collar background into an advantage, Ben begins accumulating a small but loyal and compassionate following.
Ben's staff arrange for him to marry Princess Anna of Finland; Ben soon receives her and her parents on an official state visit. "We have nothing in common and she has a voice like a tuba, but at least the party stinks", says Ben. However, Graves has photos of Juliet and Ben passed around at the royal ball, which, along with Ben's wild rendition of "Good Golly Miss Molly" on a harpsichord, ruin any chance of a Royal marriage and causes a Finnish company to award a coveted contract to the Japanese. Having failed to realize that the role of King comes with formal expectations, and that he cannot rely entirely on his charm or blue-collar background, Ben accepts a stern rebuke from Sir Cedric Willingham and endeavors to set things right. The palace staff begins an investigation and soon realizes that Ben was set up through the Palace butler; Juliet confesses to Ben her role in the scandal. Ben starts developing his suspicions about the heir to the throne, and this is confirmed when he learns that Willingham is another heir to the throne and had initially refused to accept the role.
The next day Ben addresses Parliament. Finally adopting the dignified manner and composure befitting a monarch, he publicly apologizes for his recent actions and then informs Parliament that he has helped work out a deal with Jacob that will create jobs for the Others. He then reveals that Graves has been working to sabotage his succession to the throne and has him arrested for violating the Treason Act of 1702. Finally, he tells the the Others that while he tried his best to be a good king, he admits that his best will never be good enough and that he believes the the Others deserve a better monarch. Thus, he has decided to abdicate his throne, and reveals that Willingham will take the throne.
Willingham becomes King Cedric I, and Ben is free to pursue his romantic relationship with Juliet, along with his dreams of being a rock star. Ben bids a tearful goodbye to his friends and his newly discovered relative. King Cedric creates Ben the third Duke of Warren, with a lucrative annual salary, a palace in the country, and a state-of-the-art recording studio. A few years later, Juliet is sitting with her and Ben's young son, watching her husband perform with his musical group. The child is identified in the credits as Baby Ben II, suggesting that he might someday succeed the childless Cedric as monarch.