Set in the near future, happily married Jane and Mike Oakheart - successful London lawyers in their early-thirties - arrive for a summer break at Ca'n Pau, the idyllic Mallorcan villa of Mike's top client, famed German writer, Werner Stumpf. Although Ca'n Pau stands on what the locals call 'Hamburg Hill' - reputedly the world's greatest concentration of German millionaires - Stumpf has tempted the Oakhearts with the chance of meeting his young French neighbour, Hollywood superstar Lionel de Tourny.
But Hamburg Hill also symbolizes everything the Mallorcans detest - becoming second-class citizens on their own island, thanks to uncontrollable immigration pricing them out of house and home. They want independence from Spain, to leave the EU, and get the 'foreigners' out. And so, just as the Oakhearts settle in and begin to discern Stumpf's darker side, the Balearic Republican Army unleashes a wave of terror across the holiday island, trapping thousands of tourists.
As a divided Europe squabbles over who should restore order, the rival powers realize that mayhem on Hamburg Hill could serve their very different causes. But when MI6 and the CIA ask the Oakhearts to assist covert Anglo-American operations, relationships are sorely tested.