It is 1911. Returning to Britain from Africa, Erasmus and Roka find themselves thrown into a perilous sequence of chase, capture and escape. Yet they must return to Sheffield as fast as they can, and in secret, there to prepare for an inevitable confrontation inside Sir Tantalus Blackmore's Factory. But it is not only Sir Tantalus whom they must face. As the British Army, automaton horrors, and a band of desperate Marxist engineers...