Catweazle was a magician who lived in the eleventh century, but however hard he tried, his spells hardly ever worked.

Then one day was different. First of all he had two bad omens — a bad dream and an owl hooting in daylight. Then Norman soldiers tried to capture him, so in desperation he used some magic, and it worked! The only trouble was that it had worked in the wrong way: Catweazle flew through Time instead of Space, and ended up in a place called Hexwood Farm, nine centuries later, where of course he thought everything he saw — motor cars, telephones, electric light ('Electrickery') — all happened by magic.

How Catweazle is befriended by the farmer's son, Carrot, and how he finds his feet in the twentieth century, while hiding from the world in a water tower, makes a riotously funny story, as anyone who has watched the London Weekend Television serial of Catweazle will know.