Mary Santiago (Selena Gomez) is the main character of Another Cinderella Story who the story follows. She becomes the ward of has been pop star Dominique Blatt after her mother, a background dancer of Dominique's died.
Dominique took her in but made her act as a maid/personal assistant to her and her daughters whilst she's not at school. Mary's dream of becoming a dancer like her mom came true when she was accepted into a dance school, courtesy of a contest held by Joey Parker, a famous popstar/Mary's love interest.