A chance meeting with a Schlecht agent forces a humble coffee shop manager into the secret world of spies in Swinging London. With the help of his MI5 friend, he poses as the recently dead Major Cavendish who had managed to infiltrate the dreaded organization; he knows that they are intending to assassinate someone - could it be the famous Russian ballerina who has recently arrived for an appearance at Covent Garden?

In early-twentieth-century middle-Europe, villagers are literally becoming petrified. Although the authorities try to hush the matter up, it is apparent that at the full moon, Megaera, a Gorgon, leaves her castle lair and anyone looking on her face is turned to stone. When this fate befalls a visitor, experts from the University of Leipzig arrive to try and get to the bottom of it all.