On a lovely spring morning in Cambridge, ten year old Louis discovers a trio of small talking creatures in the back garden. They are peaceful and friendly, but Denver the labrador is particularly curious and coming too close he instantly vanishes inside the aliens' portal. Louis goes after him and soon finds himself travelling through a wormhole in space to the other side of the universe. He arrives in a world of wonder such as never been seen before. The skies, lands and seas are picturesque and dreamy in glorious colours. But the Kingdom of Spalenia, where the aliens live, is under threat from the evil Lord Roga who who will stop at nothing to become king. Princess Teela, the rightful heir to the throne is captured by Lord Roga's minions and locked away in a dungeon deep underground. In a land of mystery, magic, monsters and mayhem, Louis has the task of finding the princess and rescuing her from Lord Roga's wicked clutches. Along the way, Louis has an incredible adventure including a big party with the musical Kattathons, swimming with fruit eating river sharks and dodging creatures on the Astrapios Glacier. But there is not much time to enjoy the wonderful spectacles of Spalenia, as the imperial coronation ceremony is only a few moon cycles away. In order to complete the mission, Louis must evade armies, spies and assassins and survive a final showdown with Lord Roga at Kappodeimos. Louis never thought of himself as much of a hero. In the beginning he thinks he has taken on more than he can handle. However, as events unfold and with a little timely encouragement from some friends, he learns to think of others and to trust his abilities. Most of all, he starts to believe in himself, which is just as well, because this is the time for a descendant of Zeus.