It's 1912 and 19-year-old Francis Ouimet (SHIA LABEOUF) is an Irish immigrant in Brookline, Massachusetts who works as a caddie, much to the dismay of his traditional father Arthur (ELIAS KOTEAS) who thinks he should get a real job and stop dreaming of becoming a golfer. Francis' mother Mary (MARNIE MCPHAIL), however, has always quietly supported his dream that even included keeping him out of school as a boy one day so that he could go and see his idol, British golfing champion Harry Vardon (STEPHEN DILLANE).
Francis gets his shot at fame when one of the golfers where he works encourages him to enter a tournament as an amateur. Despite others' objections, including from the father and brother to socialite Sarah Wallis (PEYTON LIST) who's drawn his attention, Francis begins play with the agreement with his father that if he loses, he'll give up the game for good. Unfortunately for him, he doesn't make the cut.
A year later, Francis works in a sporting goods store where he's approached by a representative from the U.S. Golfing Association. It seems that they want a local entrant for the 1913 U.S. Open and think he's the right fit. After some soul searching and despite his earlier agreement with his father, Francis decides to play. With the tutelage of old golf pro Alec Campbell (LUKE ASKEW) and stuck with the young and diminutive but wise for his years Eddie Lowery (JOSH FLITTER) as his unlikely caddie, Francis enters the tournament.
But the odds are against him. Not only must he face current U.S. champion John McDermott (MICHAEL WEAVER), but also a trio of British ones including Vardon, his friend Ted Ray (STEPHEN MARCUS) and their country's young champion Wilfred Reid (GEORGE ASPREY). With the command from Lord Northcliffe (PETER FIRTH) to win one for their country, the three set out to battle the Americans, unaware that their biggest challenge will come from none other than Francis.