Horse Under Water

by Len Deighton

The plot centres on retrieving items from a [[Type XXI U-boat]] sunk off the Portuguese coast in the last days of World War II. Initially, the items are forged British and American currency, for financing a revolution in Portugal on the cheap. Later, it switches to heroin (the "Horse" of the title), and eventually it is revealed that the true interest is in the "Weiss list" – a list of Britons prepared to help the Third Reich set up a puppet government in Britain, should Germany prevail. Thrown into the mix is secret "ice melting" technology, which could be vital to the missile submarines then beginning to hide under the Arctic sea ice.