Erika was a lonely indentured servant with an incredible voice. Although she wanted to travel the world and become a famous singer, she was tied to her master, the cruel dressmaker, Madame Carp. This all changed one fateful day, however. Erika was singing for coins in the marketplace when she ran into none other than Princess Anneliese, who had escaped from the palace for a day to enjoy some freedom before she was forced to marry King Dominick,a total stranger.
Erika and Anneliese realize that they have a lot in common, the most obvious thing being that they look identical to each other, with one exception--Erika is brunette and Anneliese is blonde. The two bond when they realize that they both dream of freedom, but are bound to their responsibilities. Anneliese has resigned herself to marrying Dominick as planned, but plans go terribly awry when her mother's corrupt advisor, Preminger, has Anneliese kidnapped, reasoning that if Anneliese were to "run away," Dominick would cancel the wedding, and then he could marry Anneliese and inherit the kingdom.
What Preminger didn't bargain on was Erika. Anneliese's best friend, Julian, approaches Erika, telling her of his suspicions that Anneliese was actually kidnapped, not that she had run away. He asks Erika to double for Anneliese until he can find her--and Erika's whirlwind adventure begins.
Once in the palace, Erika begins her princess lessons. She's fitted out with a blonde wig and new wardrobe, but even though she's grateful to be waited on hand and foot for once, she finds that fitting into the Princess' shoes is a lot harder than she would have bargained for. Her streetwise ways have a habit of peeking out, from her friendly interactions with the servants to her not-so-dignified ways of walking and talking. She fears that she will never be able to convince the Queen, or King Dominick for that matter.
However, Dominick is besotted with Erika's warm and open personality, and Erika finds herself falling in love with the King.