Fifteen-year-old Billi SanGreal never meant to make history. Dragged at the age of ten into the modern-day Knights Templar by her father, the Grandmaster, Billi's the first girl ever to be a Templar warrior. Her life is a rigorous and brutal round of weapons' practice, demon killing and occult lore - and a lot of bruises. But then temptation is placed in Billi's path - an alternative to her isolated life. But temptation brings consequences. In this case - the tenth plague - the death of all first borns and so Billi must choose her destiny. And as she soon discovers, death isn't even the worst.