When Mr Browser, Class 8's teacher, wishes for a brain sharpener for his pupils, he doesn't really expect his wish to be granted. So imagine his surprise when the Brain Sharpeners arrive on the school field in their space craft in answer to his call. To his delight, Class 8 is transformed by contact with the Brain Sharpeners into the cleverest children the school has ever known.
But one of the children, Michael Fairlie, has refused to be brainwashed, and he alone knows what the Brain Sharpeners have in store for Class 8. How can he save them from their fate?