A Confluence of Obsidian (The Obsidian Sisterhood, #3)

The enemy of her enemy is not her friend ... but they may be her only hope.

Sister Monica has defeated the dark Mages' attempts to seize the magickal stone she holds ... so far. But victory has come at great personal cost, and one of her own has been kidnapped.

Now, in exchange for Talia's return, Monica's enemy demands not just the stone, but the ancient and powerful Methuselah to wield it for them. If she hands them over, the Mages will have unimaginable, awful power. If she doesn't, Talia ...