Through the mists of time, the last Templar and an Irish nun hunt an ancient, immortal evil.

Tormond MacDonald, the last of the Templar Knights, was commissioned as Carnifex Dei, the Executioner of God, at Acre in the 13th century. His sacred mission - family, love, even his brother Templars - to fulfill his sacred vow, and he has pursued the enemy, a trio of witches, through the centuries. But always they elude him.

Maebh O Broin, a 15th century nun, fleeing a different, undying evil, encounters the fearsome Executioner. They are thrown together by fate - or perhaps by Providence - and together, they travel the centuries. Every time they appear, they find a wrong to right, an evil to combat. But every time, the witches escape them.

They run afoul of a demon, dealing a crippling blow to her malevolent designs. The demon plans her fiendish revenge upon Tormond and Maebh, and though it takes centuries . . . she will have them.