England, May 1643

With the country riven by civil war, word reaches Royalist headquarters in Oxford that the Parliamentarian commander Sir William Waller plans to capture the strategic city of Worcester.

Sir Philip Lord, a mercenary commander with a mysterious past, is sent to help prepare Worcester to withstand a siege. With Lord is Gideon Lennox, a young lawyer, who has been helping Lord unravel the secretive conspiracy that has overshadowed his life.

Gideon is seeking clues to that mystery when a young woman is killed, leading him to fear for the safety of his own beloved, the unattainable Zahara.

Tasked to unmask the murderer, Gideon finds his two investigations lead to the same house – that of the puritan preacher Nehemiah Fisher and his wife Joan. But another death results in Gideon himself falling under suspicion.

When one of the women close to Lord is attacked, the killer leaves a clue, but the finger it points leaves Gideon in a bleak place. If he brings the murderer to justice he risks losing the final chance to uncover Lord’s heritage.

But when the confrontation comes, all choice is taken from him. Facing the murderer alone, Gideon has to unleash his own inner darkness if he is to survive.