"I have come to ask a favour of you . . ." It is a night for visitors for Jem, the shoemaker's boy, working alone in his father's famous shop. First, three strange green children ask him for a set of silver keys, which he knows nothing about. Then a black knight comes requesting a fine pair of boots - and also asks for keys. But the third visitor proves to be the strangest - and most magical - of them all . . .