In 1988, Paul Ashworth is an English teacher where new history teacher Sarah Hughes has just started. From the first day of class they clash. His classroom is lively and boisterous, chanting for Arsenal F.C. which she says distracts her students.
Sarah complains about him to her flatmate Jo, who jokingly says they'll end up shagging. Paul talks about her to his friend Steve, saying that although she's pretty, they mutually hate one another. Steve suggests it is a promising sign.
In flashbacks, we watch Paul as a child as his dad, who he only sees sporadically as his parents are divorced, tries to connect with his children. Initially disinterested, when he is taken to a match, he loves the whole rowdy, lively experience.
In the present, Robert from the school team Paul coaches asks him to take him to a match, which he says no, sorry he can't. Discussing him with his mother, she is concerned. Paul says that, although he has poor penmanship, he's doing fine in his class. He suggests she take him to the next match as she's separated from his dad, to cheer him up.
After Parents Day, Paul offers Sarah a lift home as it's raining. She complains that, although she'd prepared, the parents preferred talking to him over her. Sarah invites him up and, as Jo isn't home, they sleep together.
Paul is offered the position of Head of Year, which he's not too interested in. When they've been together over 6 months, Sarah suggests they plan a trip somewhere. In the meantime, she goes with Paul to a match. The shoving and fanaticism makes her nervous. When it's discovered that over 70 fans were crushed to death at another match that same night, Sarah's incredulous that it doesn't dissuade Paul from attending matches.
Sarah discovers she's pregnant and is unsure of what she wants to do. Paul is enthusiastic and declares they'll have to marry and have it, but she fears he wouldn't be available for the long haul. He approaches the headmaster, saying he has changed his mind about the promotion. He is pleased until he tells him why, the upcoming baby.
The same day Paul interviews for the job, he finds they turn him down then Arsenal loses an important game, worsening their chances to win the championship. Sarah comes over in sympathy over the interview, but the Arsenal loss is what is upsetting him. They argue and she leaves.
Paul and Sarah don't speak for some days. The school's big championship final comes. Sarah comes for the last few minutes, however Robert misses the penalty kick and the match. Paul asks him if this match or the Arsenal-Liverpool league championship is more important to him, his answer is the latter. So he suggests he focus on the bigger game.
Just before the match that will decide the League Championship in Liverpool, Sarah checks in with Paul. Unsure if she'll be able to see it, she wishes them luck, knowing the team must win by 2 goals. Everyone who's watching the match is all nerved up, even Sarah discovers the team is one up in the last half. She grabs a taxi to Paul's arriving with one minute to spare. Sarah's buzzing up at such an inopportune moment earns her a myriad of profanity out the window.
Suddenly realising it could be Sarah, Paul goes down to catch her, but she's gone. Hurrying upstairs, he just manages to see the winning goal. The first time they've won after an 18-year-drought, the city comes alive with excitement, as Arsenal fans pour into the streets. The initially saddened Sarah gets swept away by the wave of supporters.
Paul and Sarah find each other and kiss. From then on, he moves on with his life. Paul's happiness is no longer dependent on Arsenal.