“Follow Big Blue”. These were the last words that Cam's father said to him. So Cam follows Big Blue, the giant whale-god, as does everyone else on Cetacea, an island in the flooded future.

The islanders’ lives play out under Big Blue’s rules, which are communicated to them by the enigmatic whale-talker, Byron Vos. Byron was once a marine scientist and is now organising an epic clean-up operation to revive the ocean after centuries of human greed and neglect.

But, as the story unfolds, Cam begins to wonder if all is not quite as it seems. Could there be a more complex truth behind Byron’s actions? A truth that may be connected to Cam’s father's disappearance?

Cam's quest to understand life under Big Blue leads him to new friends and shared adventures - but the truth, when he discovers it, turns out to be far more dangerous than he ever could have imagined.