Denis “Citizen” Hogan, a condemned man in his native Ireland, now lives in Algeria as a respected officer in the French Foreign Legion. When Hogan receives a disturbing telegram, he bids goodbye to his comrades, saying that he must return to Ireland to kill a man. Meanwhile, Lord Justice James O'Brien, Baron of Glenmalure, guilt-ridden and cursed by the Irish as “Jimmy the Hangman” because of his ruthlessness in sentencing men to the gallows, is told by his doctors that he will soon die. His daughter Connaught and neighbor Dermot McDermot have been in love all their lives, but O'Brien insists that she marry politically connected wastrel John D'Arcy, recently arrived from Paris. Despite her love for Dermot, Conn marries D'Arcy to give her father his dying wish. After O’Brien’s death, Conn continues to live in “Hangman’s House,” but is married to D’Arcy in name only, preferring to spend her time training her prize racehorse, The Bard of Glenmalure. Hogan, now in Glenmalure and assuming various disguises, has shown himself to D'Arcy, who is terrified. On St. Stephen’s Day, the day of the county’s cross country race, Hogan, in disguise as a blind man, asks D’Arcy if he has lived in Paris. Frightened, D’Arcy lies that he has never been to Paris. After dismissing Conn’s question about his lie, he informs an English officer that Hogan is there, leading to his arrest. Conn, as well as everyone else at the race, now shuns D’Arcy for being an informer. As Hogan is led to the paddy wagon, he amiably asks if he may watch the race, a request that the officer grants. Before the race starts, Conn’s butler tells her that The Bard’s jockey has run off. Dermot decides to ride The Bard himself, over D’Arcy’s objections and Conn’s suspicions that D’Arcy is responsible for the missing jockey. D’Arcy then admits to her that he has wagered against The Bard because there were better odds. When Dermot and The Bard win the race, the crowd erupts in cheers, but D’Arcy, who badly needs money, becomes so enraged that he shoots and kills the horse. As the crowd pushes toward D’Arcy with rising hatred, the English officer suggests putting him in the paddy wagon for his own protection, but Hogan refuses to ride with him. Sometime later, as D’Arcy is walking in town, he sees Dermot and asks to speak with him. At a local pub, D’Arcy reveals that Hogan hates him because he married his sister. Shocked that D’Arcy would marry Conn when he already had a wife, Dermot gives him money and orders him to leave Ireland. Meanwhile, Hogan is broken out of jail by his compatriots and goes into hiding. Hoping to confirm that D’Arcy and Conn were not legally married, Dermot, who soon discovers the inn where Hogan is hiding, takes Conn with him across the river to see him. Hogan welcomes Dermot, then shows him the telegram he received in Algeria, informing him that his sister had died after being deserted by D’Arcy. Even knowing that her marriage to D’Arcy was valid, Conn asks Dermot to run away with her, but he sadly takes her home. Unknown to Dermot, D’Arcy has never left Hangman’s House. He tries to force himself on Conn, but her butler and his dog protect her. She then goes to Dermot’s house to stay with his mother. Later, Neddy Joe tells Hogan about D’Arcy’s nightly ritual of taking Conn’s valuables and selling them. Hogan decides to confront D’Arcy, and arrives at the house at the same time as Dermot. Inside, Hogan sees a rag dipped in coal oil and accuses D’Arcy of planning to burn the house to the ground after removing the valuables. Hogan is about to have a duel with him when D’Arcy knocks over a candelabra and starts a fire. As the mansion quickly becomes engulfed in flames, Dermot takes Hogan to safety, but D’Arcy runs up the stairs and becomes trapped. As crowds gather to watch, D’Arcy falls to his death from a burning terrace. Freed of the past, Conn and Dermot can now marry, and Hogan returns to Algeria, leaving his beloved home.