In the town of Innesfree, Ireland, the Danaher house is ruled by Will Danaher. Big, brash and bellowing, Will tyrannizes his family and is happy to trade blows with anyone. He receives little argument from anyone except his sister, Ellen Roe. She has her brother's fiery temper. Although she obeys "the head of the house," she is determined to remain independent ("SEZ I").
A new arrival in town is John Enright — six foot three and broad of stature — who has come home after spending many years in America. He is searching for peace and quiet; specifically, he wants to buy a cottage, "White O'Morn'," which he remembers from his boyhood days. Mikeen Flynn, the local marriage-broker, has offered to negotiate for the cottage on Enright's behalf. When Ellen appears at the cottage during negotiations, Mikeen offers to negotiate for her, too, in case the wealthy newcomer is looking for a wife. Enright is immediately attracted to Ellen. Although she treats him with disdain, it is clear that Enright is going to find more than peace and quite in Innesfree.
With one eye on the lady's bank balance, Will Danaher plans to court Kathy Carey, a wealthy widow who owns the local pub. He goes to see her at the pub, where a local boy is entertaining the crowd by singing ("THE DAY THE SNOW IS MELTIN'"). Kathy owns the "White O'Morn" cottage and much of the surrounding countryside, all of which she inherited from her late, and not overly lamented, husband ("SAD WAS THE DAY").
Her lands border the Danaher farm. Danaher is angry to learn that the American stranger is trying to buy the cottage. He bids against Enright, but Enright closes the deal. Danaher tries to pick a fight with him. To Danaher's disgust, Enright will only offer his hand in friendship. Somewhat against his will, Enright admits that in the United States he was a prizefighter, an important piece of news for there is nothing that the people of Innesfree like more than a "fine, old-fashioned donnybrook" ("DONNYBROOK").
Ellen and Enright meet again, and he discovers that he has fallen in love with the beautiful colleen ("ELLEN ROE"). They see each other several times, and on Sunday morning they walk together through the countryside, instead of joining the congregation for mass. When Will hears of this, he warns his sister to go home, forbidding her to see the "cowardly" American again. There is a fierce argument between them, but Ellen will not disobey "the head of the house." Hoping to keep the peace, the kindly priest Father Finucane lends an understanding ear to Enright's furious complaint about the Irish ("THE LOVABLE IRISH").
Now it is up to Mikeen to set things right, and he hits upon a solution: if he can persuade Kathy to marry Danaher, then Danaher will free Ellen, to avoid having the two women living together under the same roof. The marriage-broker starts to put this scheme into operation by proposing to Kathy on Danaher's behalf ("I WOULDN'T BET ONE PENNY"). The only trouble is that Kathy, thinking the proposal is from Mikeen, succumbs to his charm. When Will is mentioned, she angrily brings the meeting to an end. Nothing daunted, Mikeen goes to Danaher and suggests — albeit nervously — that Kathy is willing to be spliced . . . so long as Ellen has a husband and a home of her own. Danaher, already hearing wedding bells for himself, consents to the marriage of Ellen and Enright. Left alone, Ellen declares her love for the American ("HE MAKES ME FEEL I'M LOVELY"). Before the wedding, however, there must be a traditional period of courting during which the lovers are to be strictly chaperoned by Mikeen. The courting is represented by a ballet, during which Enright and Ellen evade Mikeen. When they are alone, Enright vows his love for her ("I HAVE MY OWN WAY").
After the wedding service, there is a grand reception in the Danaher house. Old Man Toomey sings a toast ("A TOAST TO THE BRIDE"), and Danaher hands over Ellen's dowry — her family heirlooms and three hundred pounds sterling. He then proudly announces his own engagement to Kathy. To his astonishment and anger, he learns that the widow has no intention of marrying him. In fact, she is repelled by the thought. Grabbing the trembling Mikeen, Danaher realizes that he has been tricked into giving his consent to Ellen's marriage to Enright. He furiously takes back the dowry. He turns to Enright and knocks him out with a single punch. A flashback reveals how Enright, in his eighty-seventh fight, killed an opponent in the ring. This is the real reason for his refusal to fight. Shamed before the gathering, Enright and Ellen leave the wedding reception with Danaher's jeering laughter ringing in their ears.
As the second act opens, Mikeen and four of his friends, knowing the fierce pride and tradition by which Ellen lives, realize that she will not share her husband's home and bed unless she can cement the marriage bond with her dowry. To save the marriage, they decide to steal Ellen's heirlooms from the Danaher house. To bolster their courage, they help themselves to some alcoholic fortification. At "White O'Morn'," Enright and Ellen are spending an unhappy wedding night. Ellen feels that has been shamed, and she cannot understand why her husband refuses to fight her brother. Mikeen and his cohorts tiptoe deafeningly through the night, bringing Ellen's dowry furniture ("WISHA WURRA"). Thanks to their kindness, a part of the dowry is paid, but there remains the three hundred pounds, and Ellen still regards herself as a servant rather than a wife in her husband's house. Alone in her bedroom, she cries herself to sleep, while Enright angrily complains ("A QUIET LIFE").
At the bar of Kathy's pub, the widow has set her heart on marrying Mikeen. With the help of her friends Sadie and Birdy, she decides to make him jealous enough to propose to her by flirting with Danaher ("MR. FLYNN"). The scheme, pushed along by some pointed asides from Kathy's cronies, works perfectly. Mikeen asks Kathy to marry him, admitting his love for her ("DEE-LIGHTFUL IS THE WORD").
At "White O'Morn'," Ellen is persuaded that the marriage bed is more important than a dowry. She and her husband are reconciled ("FOR MY OWN"). Having fulfilled her duties as a wife, but with her stubborn pride still unbending, she tries to run away to Dublin. This provokes Enright to drag her to the Danaher farm for a final showdown. Throwing the girl at Danaher's feet, Enright announces that the marriage is over unless the dowry is paid. Will contemptuously hands Enright three hundred pounds, which Enright hands to Ellen. She throws the money into a threshing machine. This is too much for Danaher. He knocks down Enright, and the fight is on. Across fields and farmlands, the men hammer blows at each other until Enright lands the winning punch, toppling Danaher into a water trough. Although beaten, Danaher is delighted that the American has proven himself worthy of his sister. The two men stagger happily home to "White O'Morn'," where a proud Ellen awaits them.
(Adapted from the original Broadway cast album synopsis by Paul Myers)