Dick Court, a world-weary war correspondent traveling on an ocean liner to the United States, notices Catherine O'Shea below on the second-class deck dancing to music coming from the first-class area. Dick opens the gate separating the two classes and invites Catherine up. Although at first she refuses, they soon dance together. The next night, Catherine, in a dress borrowed from Dick's aunt, Fay Sims, accompanies Dick to dinner, where she confesses, to his chagrin, that she is coming to America from Dublin to be married. Benjamin McNutt, an American mayor, flirts with Catherine and then follows her to the deck for air. Shortly thereafter, Dick and Fay find Catherine standing over McNutt's prone body. Catherine says that McNutt tried to kiss her and that she pushed him back, whereupon he slipped and hit his head. When he revives, McNutt, to protect himself, says that Catherine attacked him. The incident makes Walter Winchell's column, and when the boat approaches the Statue of Liberty, both Catherine and Fay, who had been denied admission several years earlier, are sent to Ellis Island for immigration hearings before a board of inquiry. At Ellis Island, Catherine tries to embrace her fiancé, Henry Porter, whom she met when he visited Ireland, but Henry pulls away and his suspicious brother Ernest tells of their family's displeasure with the publicity. Tony Cadona, an underworld figure under investigation, offers to help Catherine, but Dick, who knows that a woman friend of Tony's died supposedly from a fall from a window, warns him to lay off. At night, Catherine confesses to Fay that should her marriage plans fail, she could never go back to Dublin and face her family. At the inquiry, Dick, upon seeing the snooty Henry, talks about his own strong feelings for Catherine, and when Ernest then refuses to let his brother marry Catherine, the commissioner is forced to order her to return home on the boat the next day. Greatly upset with Dick, Catherine refuses to listen to his proposal of marriage. Hoping to change Henry's mind about her, Catherine accepts Tony's offer to help her illegally get into the country. Dick sees them together and, after another immigrant under investigation steals keys for him from a guard, he sneaks into Catherine's room and tries to convince her not to go with Tony. She calls a matron, and Dick is locked up with the "undesirables" who are awaiting deportation. When Fay learns that Catherine is planning to swim with Tony to a boat waiting in the fog, she convinces her to let her go with them so that she can stop her daughter from marrying someone whom she feels is no good. The leader of the deportees knocks Dick out and takes the keys from him, then leads the others out of their cells in an escape attempt. Because the riot attracts the police, Tony and Catherine do not swim to the boat, but Fay, unaware that the men in the boat have left because of the riot, dives in. Meanwhile, the leader of the revolt threatens to kill Dick and some guards if he is not let out. Dick knocks the leader down and fights him, but he himself is knocked out with a gun and taken to the hospital. The riot is quelled, and Tony is captured by guards and arrested on an income tax matter. He vows to Catherine that he will see that Dick is killed. Fay, who is rescued by a tugboat, tells Catherine that Tony means what he says, and Catherine visits Dick in the hospital to warn him. He says that he is not afraid and apologizes to her. When she kisses him goodbye, as she prepares to return to Ireland, they realize that they really love each other, and they soon marry and take the ferry to New York.