Arty's class are on a hill outside Carmarthen, west Wales - the aim of the lesson is to learn about Merlin the magician but Arty has decided to hide from Morgan the school bully in a gorse bush instead. An old man with a long white beard appears and from his robe he draws a large hourglass. "Fifteen hundred years I have slept. Now is the time to find the King", he says. After agreeing to help the old man, there's a big flash and they are no longer on the hill. From the dragon's lair in Snowdonia to a meeting with Ysbaddaden, Chief of Giants, their quest to find the king takes them to dangerous and amusing places across Wales. An arm rises from the water at Bosherston Ponds holding a small gold book. "Take the book Arthur", says the old man and on the cover the words 'Everything a Hero Needs to Know'. Back on the hillside Arty is puzzled. Was he dreaming? Did he travel in time? Has he met Merlin? Is he Arthur, the hero?