Plot
In 1980, 7-year-old Ben Wrightman had just moved to Boston with his mother after his parents' divorce. His uncle Carl took him to a Boston Red Sox game at Fenway Park to cheer him up. From that day on, he was a die-hard Red Sox fan for life.
23 years later, Ben is still in Boston, working as a school teacher, and has inherited his uncle's season tickets since his death from cancer. Almost all of his possessions bear the Red Sox logo (except for his toilet paper, which is of the New York Yankees). On a school trip, Ben meets Lindsey Meeks, a successful, dedicated corporate executive, and they begin dating.
Lindsey, who knows little about baseball or the Red Sox, learns about the Curse of the Bambino from Ben's stadium friends (including Al Waterman, a sponge salesman who also narrates the story). They continue attending the games together, but tension arises when Lindsey is up for a promotion and begins working on her laptop during the game. Lindsey is knocked unconscious by a line drive foul and recovers but stops going to the games, suggesting Ben will have more fun if he goes with his friends.
Things get worse when Lindsey invites Ben to accompany her to Paris, and he declines because the Red Sox are in the heat of the pennant race. Before leaving, she tells Ben she might be pregnant. She expresses concern that he is more committed to the Red Sox than her, and days later, she calls him and confirms she isn't pregnant.
To prove he is not obsessed, Ben misses a game against the Yankees to escort Lindsey to her friend's birthday party. Ben and Lindsey enjoy the party, and after making love, he tells her it was one of the best nights of his life. Moments later, he gets an ecstatic call from his friend Troy, who tells him the Red Sox overcame a seven-run deficit in the bottom of the ninth to pull off one of the greatest comebacks in team history. Ben becomes irate that he missed such a historic Red Sox moment, blaming Lindsey for making him miss the game. She is heartbroken, and they break up.
Ben soon misses Lindsey and visits her in an attempt to reconcile. Lindsey thinks he's only there because the Sox are about to be eliminated and rejects Ben. He then plans to sell his season tickets to prove she means more to him than the Red Sox. Lindsey finds out during the celebration for her much-anticipated promotion and rushes to stop him. She buys a scalped outfield ticket and, during the 9th inning of the Red Sox–Yankees playoff game, when the Red Sox are just 3 outs away from being swept. Ben is in the stands, about to finalize the ticket sale.
Meanwhile, Lindsey drops over the outfield wall and runs across the field and around players to avoid security. She reaches Ben, tears up the contract, and tells him that if he loves her enough to sell his seats, then she loves him enough not to let him do it. They kiss in front of the entire crowd before Lindsey is arrested.
Al narrates the epilogue: the Red Sox won that game and then beat the Yankees three more times to win the American League pennant, later sweeping the National League champion St. Louis Cardinals for their first World Series title in 86 years. Lindsay and Ben travel to Busch Stadium in St. Louis for the decisive Game 4. Eventually, they marry, and Lindsey conceives a "player to be named later". Al explains that the baby will be named Ted Williams Wrightman if it's a boy, "Carla Yastrzemski" Wrightman if it's a girl, adding, "Let's all hope for a boy."
A post-credit scene shows a group of children (presumably, the children of Ben and Lindsey and their friends) chanting "LET'S GO, RED SOX!".