The perilous journey to the Grande Chartreuse monastery has forged an unbreakable bond between Isabelle and William. But the sanctuary they seek is a trap, and the King's Inquisitor, Ghislain de Arpajon, awaits them within the hallowed walls. In a final, desperate battle of wits and steel, they must unearth the Templar's ultimate truth and decide if their love, born in the crucible of danger, can find a future.