The larger-than-life Jules Verne adventure about reclusive genius Captain Nemo, his magnificent submarine, The Nautilus, and the perilous voyage he makes with a group of captive adventurers, one of which is a brave young woman disguised as a man.

Madeline attempts to stop the theft of the Mona Lisa in the Louvre, but no one believes her; so, she is sent to a finishing school in London. But now the thieves are also in London, and they will try to rob the Crown Jewels! Would Madeline be able to stop them?

塞布丽娜（Britt McKillip 配音）出生于女巫世家，家中时代成员都曾进入著名的女巫学校就读，并且以优异的成绩毕业。13岁生日那天，女巫王后出现在了塞布丽娜的面前，送给了她一支魔杖，以及一张女巫学校的录取通知书。就这样，塞布丽娜来到了学校里，在这里展开了全新的生活。
每一个女巫的手心里都会有一颗星星的标记，代表了她们的属性和特质。然而塞布丽娜的标志却只有半颗心，这让塞布丽娜感到了深深的疑惑和自卑。学校里有一个名叫尼克尔（Alexandra Carter 配音）的学生，沉默寡言的她常常受到其他同学的欺凌。塞布丽娜惊奇的发现，尼克尔也只有半颗星星，以此为契机，两个女孩成为了无话不谈的朋友。