Manuel Lopez and his son, Carlos, live in the tropics. The father is a wealthy aristocrat and high in the confidence of his government. The son is well-educated, suave and a coming writer. As an official of the government. Manuel has a party of officials to discuss the secret plans of their country's fortifications. After much discussion the meeting breaks up and Manuel locks the plans in his safe. Carlos and Bonita, the daughter of his father's friend, Rodriguez, are betrothed, according to the traditions of each family. The girl is supercilious and cold, caring only for herself, but to obey is so inherent in the boy that he never dreams of, breaking off the match. That night a party of friends assemble at the house and Manuel, going into the library, finds the safe open and in disorder, and the secret plans missing. Realizing the loss will mean dishonor and maybe death to him, he calls Carlos to him and tells of the theft. The boy, seeing how his father is distressed, forces his father to agree to his departure in such a manner that it will appear that the son is guilty, but just before leaving is given a key to the family code so that in case of necessity they can communicate without the message becoming public property. In order to foil any spies that may be on his trail, Carlos takes quarters in a tenement in the poorer district, when he arrives in America, and thus he meets Helen Brookes and her brother, Spike, who room nearby. One night as Carlos returns from the library, he comes upon the girl and her brother being attacked by the gang (of which "Spike" was formerly a member) and helps to drive the toughs off. The brother is hurt in the fight and Carlos takes him to the girl's rooms. Carlos and Helen become sweethearts, neither knowing of the other's occupation. One day Carlos sees a code message in the paper stating that his father is in town and asking him to meet him at a hotel. He dons his better clothes and arriving at the hotel is greeted by his father, Bonita and her father. There is a happy reunion and the father tells how the theft of the plans was finally traced to a servant, the servant confessing and implicating one of the lesser officials of the government. The old father is particularly pleased that his beloved son can now accompany him back home. That night, as a celebration, they go to a well-known café. While chatting, the café entertainer enters and just as Helen is in the middle of her act, notices Carlos and in a flash realizes that he is not a laborer, but a gentleman. He notices her, too, and has a hard time controlling himself, the struggle being noticed both by his father and Bonita. Carlos tells his father of the girl, but the old man tells him of his duty to Bonita, and so works on his honor that Carlos makes all preparations to leave, but just as the ship starts to leave he leaps ashore and returns to Helen. Helen has been taken home by Spike who tries to ease her grief, but he, too, is saddened by the desertion of his friend and idol. Suddenly there is a knock at the door and Carlos comes in. He tells Helen that he has resolved to become an American citizen so that he can marry her and everything ends happily.