Several hours before Game One of the World Series between the San Francisco Giants and the Kansas City Royals, the actor Paul Rudd, a Royals fan, and Jeff Foxworthy, a friend of the team’s manager, Ned Yost, arrived at Kansas City International Airport to attend that night’s game. A crowd was waiting at the gate. “I thought, Oh, no, I’ve got to do more interviews about Ned,” Foxworthy recalled. But he and Rudd walked past the throng unmolested. The mob was waiting for Sung Woo Lee, a thirty-eight-year-old merchandise manager of a South Korean duty-free store. When Lee finally walked through the terminal, he was set upon by fans and flashing cameras. “My eyes!” he said, shielding his face. “My eyes!”

Growing up in Seoul, Lee had watched an American armed-forces network to learn English. He found that the simplest English was spoken during sports broadcasts, and became a devoted fan of the Royals, not because the team was good—“Like many of you Royals fans, I was sort of . . . underdog lover? Sympathy?” he told a blogger—but because the team once shot off fireworks after a game.

This past August, he flew to Kansas City for the first time to see the team in person. The Royals promptly won seven straight games, and Lee became a local celebrity: he met the mayor, threw out a fluttering first pitch—“I am not an athlete”—and was honored by a local chef with the Sung Woo Dog, a ballpark frank topped with kimchi, pickled daikon, and a fried egg. “You can’t leave,” Danny Duffy, Lee’s favorite Royal, told him, after Lee greeted him with a sloppy kiss on the cheek. Asked what it would take to keep him in town, he replied, “Bunker to hide from immigration office?”

Lee returned to Seoul, but after Kansas City reached the Series, its first in twenty-nine years, Lee said he wanted to come back. He had a problem, though—he couldn’t get time off from his job. Royals fans, fearing that their team’s mojo would be spoiled without its human good-luck charm, launched a social-media campaign (#BringBackSungWoo), and Josh Swade, a filmmaker from Kansas City who’s making a documentary about Lee, flew to Seoul to confront Lee’s bosses. They relented, with the caveat that if the Series ended after four games “his vacation will be cut short.”

Lee’s World Series trip had become a more elaborate production than his previous visit. ESPN, which is bankrolling Swade’s documentary, upgraded Lee to business class, and a black Escalade was waiting at the curb. He wore a custom sweatshirt and baseball cap with “Super Fan” written in bold text, which a Korean merchandiser was planning to sell, and carried a GoPro on a baton, to film his journey for a Korean television network. On his previous visit, the Royals had “swept the Giants under my watch,” he told the cameras with the authority of a returning champion. He expected that they would do it again.

At the stadium, Lee made his way onto the field, where the Royals were taking batting practice, but he was too busy greeting supplicants to watch. He had not yet learned the celebrity’s polite decline—smile, wave, move on—and, after he stopped for his hundredth photo, Swade grabbed him by the shoulders and marched him through the throng. “I’m worried he’s gonna get kidnapped,” Maura Mandt, the documentary’s executive producer, said. “I’ve been with Tom Cruise, Denzel Washington, Tiger Woods, and I’ve never seen anything like this.”

Just before the first pitch, Mandt got a text from a fan who wanted to meet Lee. “Sung Woo!” Paul Rudd shouted, after Mandt led Lee to the right-field suite where Rudd was watching the game. “This is my mom,” Rudd said, of his mother, who had become a local celebrity, too, after her son invited fans to celebrate the team’s A.L.C.S. victory with a kegger at her house. Lee had seen one of Rudd’s movies recently, but couldn’t remember the title. (“He has a wife, but the relationship is going south,” he said, summarizing “This Is 40.”) A young boy wearing a batting helmet asked Lee for a photo, while an older man with a blue goatee requested an autograph. Neither bothered Rudd, who pulled out his phone and took a selfie with Lee.

In the middle of the ninth, Rudd tapped Lee on the shoulder and told him to look up: with Kansas City trailing, 7-1, the Royals flashed Lee and Rudd on the Jumbotron, their hats inverted in the manner common to superstitious baseball fans everywhere. It didn’t work—the Royals lost—and new hashtags started to creep across Twitter: #SungWooCurse, #GoBackSungWoo, #DeportSungWoo. The barbs hurt. “People say the Sung Woo magic is gone,” Lee said. He was in better spirits after the Royals won Game Two. He stayed up the entire night watching highlights, and, when Swade asked if he wanted to go to San Francisco for Games Three through Five, Lee declined. Kansas City felt more like home.