Mia Lockheart has a secret, Her mother was a Keeper, as was her grandmother - women who were warriors, healers and protectors. As Mia practices her craft among the boxers and martial artists of South London, and falls in love with her childhood friend, the fighter Nick Duffy, she has no idea that a man who calls himself Dragonfly is watching from the shadows. Adrian Ashton is a brilliant scientist, a skilled martial artist - and a modern-day vampire. With the aid of a mysterious and ancient book, he preys on other martial artists and drains them of their chi - the vital energy that flows through their bodies. Mia finds herself drawn to his dark genius. But when he targets Nick as his next victim, she is forced to choose between the two men. Soon it becomes a fight to the death in which love is both the greatest weakness - and the greatest prize.