In Another Cinderella Story, Mary Santiago (Selena Gomez of the Wizards of Waverly Place) is left in the care of a washed-up pop singer, Dominique Blatt (Jane Lynch), after the death of her mother, a former backup dancer for Dominique. When she's not finishing high school and dreaming of auditioning for the Manhattan Dance Academy, Mary finds herself playing a modern day Cinderella, at the peck and call of Dominique and her daughters, Britt (Emily Perkins) and Bree (Katharine Isabelle).
When teen pop star, Joey Parker (Drew Seeley) decides to enroll in her school and announce a big dance competition; where the winner will appear in his next video, Brit, Bree, Natalia (Nicole LaPlaca), Joey's ex-girlfriend and the rest of the school go absolutely nuts as they try desperately to grasp Joey's attention. But Joey only has eyes for one girl, a mystery girl, Mary no doubt, that he dances with at the school's black and white masquerade ball. But when Mary, or mystery girl drops her Zune, and Joey finds it, he begins his hunt to identify the girl that reminded him of why he started dancing. As countless girls attempt to identify the top four songs on the Zune's playlist, Britt and Bree find out that Mary is the mystery girl and persuade her into keeping silent when they come into possession of a video of younger Mary professing her adoration for Joey. However, when Tami (Jessica Parker Kennedy), Mary's best friend, convinces her to break her silence and reveal her identity, Joey pays little attention to Mary, and the opportunity is lost. As payback, Brit, Bree and Natalia play Mary's video at Brit and Bree's 16th-again birthday party and Mary runs off in embarrassment. But she quickly finds the strength to tell Joey the truth that he's been searching. Things start moving forward for Mary, as she receives great news that the Manhattan Dance Academy has considered her for an audition, and she and Joey begin practicing dance moves while doing her chores in order to prepare for her audition. But, of course, the Brit, Bree and Natalia, do not accept this, and put their plan into action to separate Mary and Joey for good before the audition and the big dance competition. Dominique plays her hand at destroying Mary's dreams, for selfish reason of course, by lying to the dance academy which results in a rejection letter for Mary's audition.
Heartbroken by jealous plans, will Joey and Mary find each other again? And, will Mary's dream of attending the Manhattan Dance Academy ever come true?