The Obsidian Sisterhood

At sixty-nine years old and with two black belts to her name, former nun Monica Barrett has never backed down from a fight. So when a woman turns up on her doorstep with an attacker on her heels, Monica is quick to step in. But this assailant has powers-he moves with uncanny speed, strikes with brutal accuracy, and isn't after the woman at all. Instead, he wants what she has: a smooth, flat piece of rock that she throws to Monica.

Former nun Sister Monica Barrett is the reluctant keeper of a stone that holds immense dark magick. She’d abandon it if she could, but it’s become attached to her—literally—and there are five more like it in the hands of powerful, corrupt Mages determined to control the very fabric of the world. Even if they destroy that world in the process. Fortunately, Monica’s foes haven’t been able to find the one thing they need to help them tap into the stones’ powers—a mysterious being named Methuselah, who brought the fragments to Earth millennia before. Unfortunately, neither has Monica.