As her beloved grandfather, chief of the Maori tribe of Whangara, New Zealand, struggles to lead in difficult times and to find a male successor, young Kahu is developing a mysterious relationship with whales, particularly the ancient bull whale whose legendary rider was their ancestor.

When Te Arepa Santos is dragged into the river by a giant eel, something happens that will change the course of his whole life. The boy who struggles to the bank is not the same one who plunged in, moments earlier. He has brushed against the spirit world, and there is a price to be paid; an utu to be exacted. Years later, far from the protection of whanau and ancestral land he finds new enemies. This time, with no-one to save him, there is a decision...