The pretty young Rosemary takes a job in Spain. The train journey to Malaga seems to cast a magic spell over her. For those few brief hours she knew a passionate, ecstasy with handsome Paul. But on meeting Mercedes, the girl to whom she is to be companion, Rosemary's dreams of love are abruptly shattered. For Mercedes is engaged to marry Don Pablo Iballo - who is none other than Paul himself!

Rosemary should try to teach her reticent ward the responsibility one must honor if one makes a promise -- especially the promise of marriage. But Mercedes is desperately in love with an out-of-work musician, and Rosemary, hurt and angered by Pablo's reprehensible behaviour, thinks of a revenge plan to deceive him. On the day of the wedding she changes places with Mercedes; and her face hidden by the heavy veil, the ceremony went through.

When the plot is discovered, the proud Spaniard finds he has been tricked into marrying the wrong woman, and happy she thinks she'll never have to fulfill the promises of a wife-to-be. But the cheated groom has other ideas: he does not send her reticent wife in fury like she had imagined, he believes that her should fulfil her duties to save his Spanish honor. What will happen next?