England is awash with traitors plotting to assassinate Queen Elizabeth I and bring about a foreign invasion.
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 at the behest of the Crown.
In the race to thwart the plot, who will triumph – the ruthless conspirators or the equally ruthless State?
An enthralling historical mystery with an exceptional twist, perfect for fans of S. J. Parris, D. V. Bishop and C. J. Sansom.