A strange boy hides an object under James' boat before drowning, pursued by angry unearthly seagulls. The object is a key of immense power which lets out its startling secrets slowly. James discovers that Humanity has been oppressed and imprisoned on Earth for tens of thousands of years. Using its advanced technology man's captors have periodically destroyed earths great civilisations whenever it poses a threat to their own power. But now James realises that Earth's technology has almost caught up with that of its masters and in a few years they can break free. But the captors are returning.