After Angelica Fanshawe's country noble mother chooses the Catholic faith over the Anglican law of England, her daughter becomes a royal ward of King Charles I, who allows her love marriage to childhood friend and cousin Harry Fanshawe. But social resistance to the king's absolutism, till then maintained by whip in an iron hand, culminates in a parliamentary rebellion, which spills to utter civil war. It means their utter downfall, Harry being executed because his royalist troops capitulated to military genius Oliver Cromwell's while their estate hosts the royal court on permanent flight.

The people of the besieged city of Oxford are in a desperate situation. Devastated by the King's brutal betrayal, Angelica is cast out of court, and finds herself destitute and starving. Meanwhile, divisions are beginning to split the Parliamentarians.

With Cromwell's regime firmly established and maintained by bloody military terror, its illegality is obvious to many, including Honest John Lilburn, who ends up siding with the opposition, yet secures acquittal at his jury trial despite hostile turncoat judges he brilliantly exposes. Meanwhile, Edward Sexby accepts a colonel-ship to defend England's backdoor in the Irish campaign, and remains loyal despite Cromwell making a liar of him by denying his mediating promises to mutineers, the leaders of which he executes. Angelica is nearly executed and separates from Harry in order to join the egalitarian diggers.

Cromwell's rule is ever more bloody and controversial, nobody feeling safe anymore amongst factions and treason, yet the Lord Protector achieves a monarchy in all but name. Lillburne is jailed for life without trial. Sexby resigns has colonel's commission on account of his war-wrecked hand. Plotting and discovered intrigues make many fatal victims, including Joliffe. Angelica survives everybody, alone but for Sexby's posthumous daughter.