An Irish leader falls in love with the daughter of a British diplomat during a rebellion, and a peace treaty is the result of their love.
In 1921 Dublin the Irish are resisting British occupation. British soldiers attack an office, and several are killed. Dennis Riordan (Brian Aherne) tells Cathleen O'Brien (Karen Morley) that records had to be destroyed, and her husband was killed. Riordan orders no violence against the arriving English diplomat Lord Athleigh (Henry Stephenson), but they plan to get the munitions. Athleigh and his daughter Helen (Merle Oberon) refuse to ride in an armored car. Riordan is arrested and released. The munitions are destroyed. Helen helps a boy who wrote on her car and takes him to his mother Cathleen. Riordan comes in and tells Helen the English kill and have no feelings; she condemns Irish hatred. Helen's car is sabotaged; she borrows a bicycle and is accompanied to the sea by Riordan. He invites her to the market, and she returns the bike. Talking to the boy, she learns he is Dennis Riordan. Athleigh complains to Helen about Riordan, and she says he will be at the market; but he escapes thirty men, and O'Rourke (Jerome Cowan) asks him how they knew he would be there.
Helen gets a letter from Riordan and goes out with a new chauffeur. Then she takes a taxi and tells Riordan she is his enemy. They agree not to see each other; but he wonders about their possible future and kisses her. Helen says she loves him. O'Rourke shows Riordan the police outside. They go on the roof and are shot at but hide. Riordan promises O'Rourke he won't see her again. Athleigh leaves on a ship with Helen and will recommend military action; but she pleads for peace. At a British meeting Athleigh suggests a truce, while his aide Gerald Preston (David Niven) asks Helen for advice about his new girl-friend. Athleigh says they are inviting the Irish to a conference with safe conduct to London. Riordan gets the Irish to accept.
At Athleigh's reception Riordan and five Irish attend. Preston introduces people and has Helen attend to Riordan. They hold hands; but both promised not to be alone together. The conference cannot agree; but Athleigh asks for one more meeting, and Riordan agrees. Athleigh tells Helen that war is being prepared. Riordan goes out for a walk, and Helen goes to his hotel, finding him on a bridge. She pleads with Riordan for people to live. After the meeting Riordan tells Helen they signed the treaty, and he will love her forever. Athleigh tells her that the courageous Riordan has signed his death warrant. Helen takes a ship to Ireland. Burke (Donald Crisp) says they must kill Riordan, and O'Rourke volunteers. Helen comes in and pleads for Riordan and peace; but they believe he sold them out for her. Riordan speaks to a crowd in the street for peace and is shot. In the final scene he tells Helen that he is not going to die.
This powerful story set in the historic English-Irish conflict explores the conflict between political violence and romantic love, expressing the hope that love may solve problems with peace and understanding.