Catherine O'Halloran is going to die. Twenty years ago, her sister heard a terrible wail, a relentless keening that no one else could hear. Catherine didn't believe her-until she saw a banshee crying at their bedroom window the night her sister died. Now Catherine has begun to hear the same wailing, and she knows it's only a matter of time before the same dark specter pays her a visit.

But Catherine has no intention of going gently into that good night, so she travels to Ireland for answers about the banshee's curse hanging over her family. After a near deadly attack from a malevolent spirit, she meets Liam-a Fae sent to help her. Liam tells her the terrible truth: the banshee is part of a league of Dark Fae that collects human souls. If Catherine doesn't find a way to stop the banshee, her and her sister's souls will be lost forever.

Catherine and Liam must travel through the past and into the misty Fae underworlds for a miracle. But when Liam reveals he has his own agenda in this war of souls, Catherine must decide between saving herself and her sister's soul or protecting all of humanity from darkness.