One summer day, the red-haired girl Mary (voiced by Sugisaki Hana) was sent to her aunt Charlotte's country cottage for vacation. Mary was not so used to everything around her when she first arrived, especially the naughty boy Peter (voiced by Kamiki Ryunosuke) who deliberately went against her, which made Mary really unhappy. During an accidental forest adventure, Mary saw the legendary magic flower "Night Flight" and found a broken broom. It happened that this magic broom carried Mary into the sky and came to the Ende Academy, which specializes in training magicians. In this magical place, Mary was warmly received by Ms. Manblechek (voiced by Amami Yuki) and met the weird Dr. D (voiced by Kohinata Fumiyo). Although the girl became a magic student in a daze, she soon discovered the secrets hidden here... This film is adapted from the British children's literature novel adapted from Mary Stuart. It is the first animated feature film produced and shot by Hiromasa Yonebayashi after leaving Studio Ghibli.