In his epic adventures in the alternative Twentieth Centuries, Chrononaut Oswald Bastable, member of the League of Temporal Adventurers, has crossed and re-crossed many different time-streams. Some of his previous experiences have been told in The Land Leviathan and The Warlord of the Air.Now, in what may be the last communication from him, he tells of a world in which the Bolshevik Revolution never happened...

The Steel Tsar finds him travelling backwards in time from a shell-shocked Singapore to a Russian Empire seething with conflict and preyed on by motley bands of rogues and adventurers. Here he meets up with fellow-time-traveler Miss Una Persson, and together they change the course of a history whose legendary deeds exceed the bounds of everyday imagination and glitter in the exuberant land of the eternal present.