June, 1554. Former cutpurse and now professional assassin Jack Blackjack has deep misgivings about his latest assignment. He has been despatched to the Palace of Woodstock, where Queen Mary's half-sister Princess Elizabeth is being kept under close guard. Jack's employer has reason to believe that a spy has been installed within the princess's household, and Jack has been ordered to kill her.

Jack has no choice but to agree. But he arrives at Woodstock to discover that a murder has already been committed.

As he sets out to prove his innocence by uncovering the real killer, Jack finds the palace to be a place steeped in misery and deceit; a hotbed of illicit love affairs, seething resentments, clashing egos and bitter jealousies. But who among Woodstock's residents is hiding a deadly secret - and will Jack survive long enough to find out?