Unforgiven

As Laney struggles to keep her sanity with Cas's whispers from the afterlife, she relies on her new-found friendship with Avery, the only person who misses him almost as much as she does.
Little does Laney know that her knowledge about Shadowbringers isn't even the tip of the iceberg. A whole new layer of trouble is waiting for her as she makes plans to find Cas and bring him back. But there is a new Shadowbringer in town-and if you thought Cas was bad, you haven't met Luc.