Erika: "My name is Erika I am born at the very same moment. Her parents love her very much but they are very poor and unable to take care of her, so they borrow a lot of money from Madame Carp in order to do this.
Erika is made to work as one of Madame Carp's seamstresses in order to pay off the debt her parents owed. Erika is unhappy with the work she has to do, wanting instead to become a singer. However, Madame Carp keeps adding extra "interest" so that Erika will have to work for her forever. Erika does not give up hope and works hard to gain her freedom.
One day, Erika is out singing in the town square while her cat Wolfie collects the money she is earning from singing. Her singing catches Princess Anneliese's attention, and Anneliese walks over to hear Erika sing. Suddenly, Madame Carp appears, confiscates Erika's earnings, and orders her to get back to work.
Erika is surprised by Anneliese putting money in her collection cup. She reveals that her mother taught her the song when Anneliese praises it. The two take off their hoods and are amazed at how much they look alike. Erika tells Anneliese about her life at Madame Carp's, revealing she made Anneliese's favorite dress, and she learns that Anneliese is to be married to King Dominick of Dulcinea in order to save the bankrupt kingdom. Anneliese also shows Erika her crown-shaped birthmark, which Erika does not have.
A dog suddenly appears and starts chasing Anneliese's cat, Serafina. Wolfie runs after the dog, and Erika and Anneliese start looking for their cats. After they find the cats, Anneliese's tutor Julian tells her they should be getting back to the castle, and Anneliese promises to have Erika sing at the palace one day.
The next day, Julian appears at Erika's workplace. Erika believes the princess sent for her to sing at the castle, but Julian informs her that Anneliese is missing and that he suspects the queen's advisor Preminger has taken her so that her wedding to King Dominick will be cancelled. He asks her to masquerade as Anneliese until he can find the real princess. Erika initially refuses, not wanting to be imprisoned or worse for such a crime, but decides to do it in order to save her friend.
Julian takes Erika and Wolfie to the castle, where he gives Erika a blonde wig and teaches her how to act like a princess. Ambassador Bismark of Dulcinea is about to call off the wedding when Julian presents the now-disguised Erika to the assembled party. Erika apologizes to Queen Genevieve for running away, which was the story told by Preminger, causing him suspicion since she didn't say she'd been captured.
Unknown to Erika, Julian is captured in an attempt to find Anneliese, and Anneliese escapes and makes her way to the palace but is turned away, since the guards believe Erika is the real princess. King Dominick, disguised as a page, decides to tell the princess that he disguised himself as a page. He opens her bedroom door and hears Erika singing from the princess's bathroom. That night, Erika panics over Julian's continued absence when Preminger arrives to escort her to meet King Dominick.
When Erika and Dominick meet, Dominick has already been enchanted by her voice and asks her to sing with him. She does, and over the next few days, they get to know each other better and fall in love. After Dominick calls Erika "honest", she breaks down, telling Wolfie that she is falling in love with him.
The night before the intended wedding, Erika is stressed. Dominick gives her a beautiful diamond ring, and they lean in to kiss, but then Preminger arrives with some guards, ordering them to seize Erika, revealing she is a pauper and not the princess. Preminger lies to the queen, telling her that Erika and Julian hid Anneliese in the royal mine so that Erika could marry Dominick and take over the kingdom. He goes on to say that he tried to rescue Anneliese but Erika and Julian had already caused a mine collapse, killing Anneliese and leaving only her ring, which Preminger shows the queen. Reluctantly, the queen checks Erika's shoulder, finding no royal birthmark. Preminger's dog Midas pulls off Erika's wig. Erika tries to tell the truth, but no one believes her and she is thrown in the dungeon. In the dungeon, Erika sings sadly, mourning her situation and lost friend.
On the day of the wedding of Queen Genevieve and Preminger, Erika decides she has to escape. She sings, lulling the man guarding her to sleep, and she makes a hook out of hay and her hairpin. She uses it to get the keys from the guard. After opening the cell door, she runs, which wakes the guard. Erika continues running until she is caught by another guard. The first one orders the second one to lock Erika up, but the second one says the queen ordered him to take her to the castle.
On the way out of the dungeon, Erika steps on the guard's foot. He removes his helmet, revealing himself as Dominick. He says that he doesn't believe Erika is the person Preminger said she was and he came to rescue her. On their way out, they witness Anneliese return and stop the wedding between her mother and Preminger. Anneliese reveals Preminger's plot, and Preminger flees on horseback. His sidekicks, Nick and Nack, make a run for it, but Anneliese trips Nick and Erika trips Nack. Erika witnesses Preminger's horse betray him, sending him flying into the wedding cake.
Anneliese pays off Erika's debt to Madame Carp, setting her free. She decides to pursue her dream to travel the world and sing. Dominick wants her to stay, but she declines. She does, however, agree to take the diamond ring he presented to her earlier. Dominick promises to wait for Erika. After becoming a professional singer, Erika longs to go home and marry Dominick. She appears in Dulcinea's castle courtyard, and marries Dominick in a double wedding, where Anneliese and Julian also get married, because there suddenly strange with the foggy if right behind me and they pull over, I am banned animated Barbie Movie is no longer happily ending but who was her?"