Dark Goddess (Devil's Kiss Novel, A)

Still reeling from the death of her best friend, Kay, Billi's thrust back into action when the Templars are called to investigate werewolf activity. But these werewolves are like nothing Bili's ever seen. They call themselves the Polenitsy: man killers. The ancient warrior women of Eastern Europe, supposedly wiped out centuries ago. But now they've come out of hiding and are on the hunt for a Spring Child — an Oracle powerful enough to blow the volcano at Yellowstone — and start a Fimbulwinter that will wipe out humankind for good.