Generations of Ana Dakkar's family have attended the legendary Harding-Pencroft Academy, where the best underwater explorers in the world go to train. When Ana witnesses a tragedy, her life at school and beyond is changed forever. It turns out that Harding-Pencroft and its rival school, Land Institute, have been fighting a cold war for a hundred and fifty years-and it's just turned hot.

Pursued by enemies, Ana learns her family's ties with Harding-Pencroft go deeper than she ever imagined-back to her not-so-fictional ancestor, the legendary Captain Nemo.

Land Institute will stop at nothing to acquire the secrets of Nemo's technological genius. Only Ana and her class of half-trained future explorers stand against them. And with her enemies seemingly always one step ahead, can Ana trust anyone but herself...?