Meimi, a bright and cheerful girl who inherited the magic powers of her father Gen'ichiro and the abilities as a thief of her mother Eimi, turns into the Kaitou Saint Tail (mysterious thief Saint Tail) at night to make things right. With the help and counsel of her friend Seira, she steals things back to those innocent victims who have been gone to Seira for help.
While she is as Saint Tail, Asuka Jr. has dedicated himself to catch her, for although her objectives are good, stealing is still a crime. Nevertheless, she likes Asuka Jr.
Saint Tail uses magic words and items on her missions.