Mai Kazuki, a young girl from a family of stage magicians led by her grandparents in the troupe Magic Carat, possesses magical abilities enabling her transformation into an older, teenage alter ego named Magical Emi. Her mother left magic to start a family, and Mai herself initially battles clumsiness and lacks proficiency in conventional tricks. A mirror fairy named Topo grants her a transformation bracelet, unlocking the confident, skilled, and poised Magical Emi—a state dramatically contrasting with Mai's more excitable and occasionally temperamental nature. As Magical Emi, she performs real magic during Magic Carat shows, significantly boosting the troupe's popularity.

In the OVA "Majokko Club Yoningumi: A Kuukan kara no Alien X," Mai joins magical girls Yuu, Persia, and Yumi to confront an alien entity that attacks young women, transforming them into elderly hags. Mai contributes by becoming Magical Emi for this interplanetary mission, traveling to space with the team in specialized suits provided by Yumi to combat the threat and protect Earth.

Throughout her journey, Mai's core motivation remains her aspiration to become a skilled stage magician through her own efforts, rejecting magical shortcuts. This ambition ultimately leads her to relinquish her powers and pursue conventional mastery of stagecraft. Her character is further illustrated through interactions, including with classmate Musashi, who harbors an unnoticed crush, and her close, sibling-like friendship with a boy named Sho.