Cadmus, the youngest son of King Agenor, lacked the confidence and leadership qualities that marked a future king. One day he is assigned to watch over his adventure-seeking sister, Europa, to make sure she doesn't run off to the local carnival. But Europa, having dreamt that a white bull would take her off to unknown lands, sneaks away to find her destiny, urging her brother to find his too.
At the carnival, Europa finds her White Bull, the beast that no mortal man has ever ridden. Amazingly, the White Bull lets Europa on his back. But what no one knows is that the White Bull belongs to Zeus. Determined to show this impetuous mortal what it really means to ride his creation, Zeus hurls down a thunderbolt which strikes the bull causing it to ride Europa right off a cliff and into the sea. With the help and advice of the goddess, Athena, Cadmus gains the courage to travel across a dangerous sea and a vast desert in a desperate search to find his sister. Learning of this courageous boy, a tribe of wandering nomads become convinced that Cadmus is the one destined to be their leader and defeat a terrible monster that has prevented them from settling on their land. Cadmus does not consider himself a ruler, but only wants to find his sister and go home. But fate has other plans as Europa, having become lost in the desert, arrives at the very spring where the monster lies in wait. Cadmus discovers Europa has been taken by the beast and rising above his fears, enters the monster's watery lair, conquers the beast and rescues his sister. With newfound confidence, Cadmus builds the city of Thebes on that very spring proving himself worthy to be a King after all.