Spring 1915.
Eight months after foiling a plot to delay the embarkation of France-bound British troops, and reluctantly arresting his lover's brother for being involved, Jack McColl is stationed in India, charged with defending the Empire against Bengali terrorists and their German allies. Belgium, he finds, is not the only country seeking to expel an invader.
In England, meanwhile, Colm Hanley is executed, and his sister Caitlin begins the business of rebuilding her life. The war is changing everything, and giving fresh impulse to those causes - feminism, socialism and Irish independence - which she as a journalist has long supported. The threat of a rising in Dublin alarms McColl's bosses as much as it dazzles Caitlin. It was one Irish plot which came between Jack and Caitlin in 1914, and it will take another to bring them back together, both as enemies and lovers.