James's father is missing. With no clue why his dad would run out on him and his mum, he hides out by an ancient stone circle to think. There, James discovers a dead stoat, crushed in an impossibly huge footprint. The mystery of what smashed the little animal leads James into finding Mendel, a wizard from another world called Denthan. Mendel has his own problems though. He's trapped in the body of a goldfish and Denthan's sun is about to die and destroy the planet. James is soon drawn into Mendel's plight and hopes against hope that the goldfish can somehow help him find his dad. Will Denthan be saved? Can Mendel regain his true form? But more importantly, will James ever find his father?