The first in a series about a quiet intellect thrust into a world of dark secrets, treachery, and vicious murder in the English Civil War Summer, 1643: England is at war with itself. King Charles I has fled London, his negotiations with Parliament in shambles. The country is consumed by bloodshed. For Thomas Hill, a quiet man running a bookshop in a rural town, knowledge of the war is limited to the rumors that reach the local inn. When a stranger knocks on his door informing him that the king's cryptographer has died, everything changes. Aware of Thomas' expertise in codes and ciphers, the king has summoned him to Oxford. On arrival, Thomas soon discovers that nothing at court is straightforward. There is evidence of a traitor in their midst. Brutal murder follows brutal murder. And when a vital message encrypted with a notoriously unbreakable code is intercepted, more lives are in danger. Will Thomas decipher it in time to reveal the king's betrayer and prevent another violent death?