Stalin's Hammer — John Birmingham

Ten years have passed since Admiral Kolhammer's 21st-century battlefleet was dragged into a wormhole and thrown across oceans of time, emerging with disastrous consequences and shattering the history of the Second World War.

Hitler and the Nazis have fallen, but Stalin rules half of Europe and Asia. The great Soviet engines of state power turn and burn to 'set history right'. Not just of the war, but of all future time.

In Rome with his lover, Julia Duffy, an older, mellower Prince Harry is drawn into Stalin's plans when a simple game of spies goes horribly wrong. Underneath the eternal city, former Spetsnaz officer Pavel Ivanov fights a running battle with the NKVD's executioner in chief as Stalin's minions fight to preserve the secret of a weapon that could destroy the West with one fearsome blow.

Moving from Rome to Paris to Cairo, Harry and the uptimers must fight a shadow war against the communist superstate and the suspicion and prejudices of their forebears. They can save the world, but the world does not want saving by the likes of them.