Oxford, Autumn 1353. St. Frideswide's Fair is a great annual event in Oxford, bringing together merchants and buyers from all over England and Wales, and from as far away as Flanders and France. Yet the earnings from the fair, granted to the Priory of St. Frideswide centuries before, are resented by the town, and resentment can turn to violence. Under the unscrupulous Prior de Hungerford, even more trouble is brewing.

Facing the threat of King Philip's Enterprise of England - Spanish invasion and annexation of the country - Sir Francis Walsingham's secret service spreads a network of agents across Europe. After caring for hundreds of maimed and wounded soldiers returning from the fall of Sluys, young physician and code-breaker Christoval Alvarez is sent on two dangerous missions to Amsterdam, where, amongst the friendly Hollanders, treason and treachery lurks.

In Elizabethan London, no child is safe. Children are misused and exploited by parents, masters, strangers, and society at large. Even the children of the rich are in danger. When a five-year-old heiress to great estates is kidnapped, Christoval Alvarez, the players of James Burbage's company, and a disreputable group of child beggars all become involved in the search. At Seething Lane, matters are approaching a crisis.

It is the year 1586. England is awash with traitors, plotting to assassinate the Queen and bring about a foreign invasion. The young physician Christoval Alvarez, a refugee from the horrors of the Portuguese Inquisition, is coerced into becoming a code-breaker and agent in Sir Francis Walsingham's secret service. In the race to thwart the plot, who will triumph - the ruthless conspirators or the equally ruthless State?

When Bartholomew Fair, London's largest public festival, is threatened in 1589 by 500 armed soldiers dismissed from service without pay, the authorities act swiftly and decisively to prevent trouble. Yet other trouble is brewing. Young physician and code-breaker Christoval Alvarez stumbles upon a sinister troupe of Italian puppeteers bent on making mischief, but it soon becomes apparent that more than mischief is in the air.