Based on Martin Maher’s autobiography and directed by John Ford, a man from Ireland gets a job at West Point, marries a woman from Ireland, and keeps enlisting in the army and working with the athletic teams.
Aged Marty Maher (Tyrone Power) tells President Eisenhower (Harry Carey Jr.) he is not ready to retire even though he is over seventy. He says he arrived at West Point fifty years ago, walking with a suitcase after just coming from Ireland. Marty observes the cadets and their discipline, and he gets a job serving food. He breaks so many dishes that he gets no pay in the first two months. The paymaster loans him $3. Rudy Heinz (Peter Graves) demands the $5 owed him and hits Marty, breaking more dishes.
Captain John Pershing (Milburn Stone) swears in Marty for enlistment. Marty finds the cannonballs too large for the cannons. Marty stands guard duty at a dance. Jim O’Carberry tells Peggy he loves her. Marty sees Jim walking punishment. He calls Heinz an informer and slugs him. Marty is put in the guardhouse, and Jim tells him he turned himself in. Captain Kohler (Ward Bond) teaches Marty boxing by knocking him down several times and gives him a job. Marty meets Mary O’Donnell (Maureen O’Hara), and she watches him teach boxing. Marty learns Kohler hired Mary as a cook, and he offers to help around the house. While he fixes the plumbing, he talks to Mary. At the field he talks to her again, but she does not respond. He says he is leaving and invites her out. She opens her basket and goes off with Rudy. Marty tells Kohler he is re-enlisting.
In the evening Marty hears Mary singing and sits by her on the porch. Without looking at him she says, “Yes” and starts talking to him. She asks to be kissed, and he says he does not have much money. He suggests they could save and go back to the old country, but she likes it there and suggests they bring his father over. He learns Kohler arranged for them to have a place, and he kisses her.
Marty tells Mary that $300 is missing, and she shows him that his father Old Martin (Donald Crisp) and his brother Dinny (Sean McClory) are there eating. They say a blessing.
Kohler has Marty teach swimming and pushes him in the pool. James “Red” Sundstrom (William Leslie) shows him he can do the Australian crawl. Red is upset because he is behind in his studies. Marty invites him for dinner. Marty falls in the pool and has to be rescued. Marty brings Kitty Carter (Betsy Palmer) to dinner to meet Red. Marty says Kitty is a college graduate, and she offers to tutor Red.
In 1913 their football team plays Notre Dame in the mud. Old Martin bets on Notre Dame. In the second half Notre Dame starts passing the football. Kohler says it is legal. Rockne catches passes, and Notre Dame wins. Kohler tells his players to learn to expect the unexpected. Marty bandages Chuck Dotson (Phil Carey) and urges him to quit football and work on his studies.
Dinny arrives in a new car, and Old Martin scolds him. Dinny is making money, and Marty wants to do so also. Old Martin says Mary is going to have a child. Red and Kitty wait nervously, and Marty comes in. Old Martin comes in and says he is a grandfather of a boy. Cadets arrive, sing to Marty, and give him a sabre. The doctor arrives and tells Marty his son died. Marty goes to a bar and gets drunk. Cadets come in to take him home.
Marty sees the cadets walking punishment, and he takes flowers to Mary, who says she cannot have another. He moves her bed by the window so that she can see the cadets marching. She says they have many fine boys there.
The class of 1915 graduates and includes Omar Bradley and Dwight Eisenhower. The class of 1917 graduates early, and they go off to war in France. Cherub Overton (Patrick Wayne) gets his first salute from Marty. Mary cries as they board the train. Marty asks Kohler what happened to his transfer, and Kohler tells him he is needed there. Kohler is leaving to train troops in the camps. Old Martin is enlisting, but Marty tells him to stay and help him.
Marty sees a list of the killed and wounded in March 1918. At home he and Mary mourn the losses. Kitty comes in and says Red and Cherub were in Paris. They say Old Martin is working with horses.
Cadets celebrate the end of the war, but Marty mourns the death of Red Sundstrom. Marty says he wants to leave. Old Martin says he is staying. Marty asks for his father’s blessing, and Marty and Mary leave in a car and visit Kitty, who shows them the medal of honor. Marty says her son has an appointment to West Point. Marty invites Kitty to visit them at the Point, and he says he will re-enlist.
Years later James Sundstrom Jr. (Robert Francis) is sworn in as a cadet. Marty sees him go out with a girl. In church a message is delivered, and the priest announces the Japanese attack on Pearl Harbor. At the cemetery James asks to talk with Marty. James says he was married, and it was annulled. Marty tells him to listen to his conscience. At night Mary answers the phone and tells Marty that Kitty is coming over. Marty says that James is dishonored, but Mary warns Marty not to harm him. James and Kitty come in. James says he is a new recruit, and he says goodbye.
A tour guide introduces Marty and mentions the tradition of Col. Kohler. A young governor complains about tradition, and Marty lectures him about the cadets who lead in battle. At home Mary tells Marty she is going to the parade, but he wants her to stay in bed. She asks him to help her to the porch. He goes in for her medicine. She looks at the cadets. As he is returning, he sees her die.
At Christmas time Marty stops in church to pray on his way home with groceries. Cadets come in and help him in the kitchen. Young Dotson gives him a present from his father in Belgium. Big brass arrives in the persons of Kitty and James, who has a wounded leg and plans to go back as a captain. Kitty takes charge, and they bring in a Christmas tree. They sing a merry Christmas to Marty.
Elderly Marty tells President Eisenhower that West Point has been his whole life. An officer tells Marty he is AWOL and takes him back. On the field the band plays an Irish jig and other songs for Marty. Kitty and James are there. Marty sees young Mary, his father, Kohler, and cadets who had died.
This sentimental drama is the true story of a man who became such a part of an institution for so long that he became an institution himself.