The Keeper: A Martial Arts Thriller by Natasha Mostert

"From the award-winning author of Season of the Witch, comes a highly original martial arts thriller, blending magic, science, chi and the greatest desire of all: to live forever. Adrian Ashton is a brilliant man: a chronobiologist who has devoted his life to the study of chi — the vital energy that runs through our bodies. A gifted scientist, he is also a skilled martial artist — and a hunter. Calling himself Dragonfly, he preys on fighters and martial artists who are blessed with a strong life force, draining them of their chi and making it his own. But the hunter becomes the hunted when a mysterious woman enters his life. A martial artist herself, she belongs to a long line of Keepers: women who are warriors, healers and protectors. When Dragonfly targets the man she loves, she sets out to defeat him. It becomes a fight to the death in which love is both the greatest weakness and the biggest prize."