Having shot someone in the chaos of 1963 Berlin, Wilderness finds himself locked up with little chance of escape. But an official pardon through his father-in-law Burne-Jones, a senior agent at MI6, means he is free to go - although forever in Burne-Jones's service. When the Russians started building the Berlin wall in 1961, two 'Unfortunate Englishmen' were trapped on opposite sides. Geoffrey Masefield in the Lubyanka, and Bernard Alleyn (alias KGB Captain Leonid Liubimov) in Wormwood Scrubs. In 1965 there is a new plan. To exchange the prisoners, a swap upon Berlin's bridge of spies. But, as ever, Joe has something on the side, just to make it interesting, just to make it profitable...