Mariah Mundi has no choice but to unite with the enigmatic Will Charity when his family is kidnapped by an unknown enemy. Their adventure leads them to the mysterious and majestic Prince Regent, a huge steam-powered hotel on a small island at the furthest reach of the Empire. Mariah, with the help of Sacha, must unravel the secrets of the island to find the truth behind the disappearance of his family, and prevent Otto Luger from getting his hands on the mystical and powerful Midas Box.

At the end, Will leaves to search for the boys’ parents, who are still missing. He promises to return for Mariah. A mid-credits scene reveals that their mother has been taken to Egypt by the villain Gormenberg—her husband, the boys’ father.