“No matter how small you think you are, you can all change the world with one single thought or action. All you have to do is believe that you can. Therein lies the magic.”

Dylan McFinn is an ordinary twelve-year-old. Ordinary, that is, if you ignore the fact that he lives deep under the Pacific Ocean with his sea-captain father Culbert, his annoying little brother Axneus, and his mother Varuna – who is most definitely not a mermaid.

Ordinary, too, if you ignore the mysterious power he doesn’t know he possesses.

For Dylan’s birthday, Culbert takes the family on a trip to his homeland. He remembers the island of Maloto as a beautiful, tranquil place, but something has changed in the fourteen years since he left. Dark forces are threatening the peace, and his old friend Marvin – an environmental warrior last seen fishing plastic from the ocean – has disappeared.

Axneus, though, seems more interested in the shiny black stone he stole from Eric at Neptune’s Tower. What is its secret? And where exactly is Neptune’s Tower, anyway?

As he battles monsters and maelstroms on his first day as a teenager, Dylan McFinn discovers that he can be an awful lot more than he imagines and a nostalgic trip to the past was more than just a rite of passage. It was a passage to his destiny.