Oliver Cromwell has died, naming his son Richard as his successor. Few believe he can last as Lord Protector and the country is split between diehard royalists and republicans, with many in the middle willing to countenance the return of Charles II on suitable terms. John Fenwick is asked to find a man engaged in discussions about these terms, but realises he's being used to give credit to a ruse. But when the man turns up dead and mutilated, in the spot where Charles I was executed, he is prepared to investigate. But the dead man was out for himself and might well have been a double- or treble agent. So who killed him - diehard royalists or republicans, or the people he was helping to agree terms on which Charles II might be restored to his throne who felt he was betraying them - lies in a fog of treachery and deceit. His investigations are also hindered by diehard Royalists intent on killing him. Eventually he finds his way through the fog - to someone who has been misleading him all along.