A giant wave leaves Shunda, a young aquavian, orphaned and alone for 12 years. In search of his kin, he swims to the land of Hoondiake and finds himself at the centre of a great battle. In Loesheen, a month's swim north of Hoondiake, the Ancient MerKing of the deepest sea has enslaved aquavians, the most peaceful of all creatures of Aiqua Marrin, and twisted their minds to fight on the land of Hoondiake, where mermen cannot breathe for long. He discovers deep friendships, desperate enemies and captives, indeed a whole world, on the verge of freedom.