Songbird (Shiloh) by Helena Sorensen

The Shadow's hold has grown strong over Shiloh. For many long years, the Bright Immortals have waited, and at last Ram has allowed them to intervene. At their behest, Simeon crafts the Singing Stone, and Isolde goes back into the Shadow to call the Children of the Morning to freedom, to light.

But the Wolf is cunning and his allies have made ready. War is coming for Isolde's sister, Rosalyn, for faithful Orin, for Eve and Merrick, and the few remaining warriors who refuse to be silent. Will they find the strength to stand against the last and greatest assault of the Dark Immortals?