Billi SanGreal is the only girl in the Knights Templar. At fifteen, her life is a rigorous and brutal round of weapons practice, demon killing and occult lore. But then she didn’t have much choice: her father, the Grandmaster of the Order, forced her to take this path.

There is no sacrifice Arthur will not make in his war against the Unholy. But Billi hates the Order, and she hates him too. Tempted by a chance to live a different kind of life and reject everything her father wants her to be, she learns to her horror that she may unwittingly have brought down the tenth plague upon humanity – the death of all first–borns.

Faced with choosing her destiny, she soon realises that even death may be no escape.