A girl returns from boarding school to her sleepy Merseyside hometown and waits to be reunited with her childhood friend, Harriet, chief architect of all their past mischief. She roams listlessly along the shoreline and the woods still pitted with wartime trenches, and encounters 'the Tsar' – almost old, unhappily married, both dangerously fascinating and repulsive.
Pretty, malevolent Harriet finally arrives – and over the course of the long holidays draws her friend into a scheme to beguile then humiliate the Tsar, with disastrous, shocking consequences.