Five years ago, the Sanctuary's war ended. That's when the battle for the alt-worlds began.

Led by an unlikely Master Capturi, specialized teams of cavali use new magic to hunt their remaining enemies in the alt-worlds. For Piper, bringing the assassi to justice has become her life's mission. But while she battles murderous gods, the fairies of the Sanctuary flounder without a queen. They want her back, but Piper holds a secret that, if exposed, would turn the fairies against her. Can she hide the truth and lead her sisters by example? Or is she not a true fairy herself?

Meanwhile, on an alt-world far different from the Sanctuary, Namenye of Oak has her own secrets, and Piper is in for a surprise...

Dryads, naiads, and oreads ? paranormals thought to be extinct ? await Dax and Piper on this next alt-world. The assassi? She's a goddess of immense power and cruelty who has tormented these remarkable peoples for centuries. Her Devout are forced to sacrifice dryads for their magic. Oreads who've escaped the goddess live as refugees. Dryad knights patrol the border. Naiads cloud their waters to blind the goddess's all-seeing slave. With every sacrifice, the goddess grows stronger.

Piper, Dax, Namenye, and their allies ? old, new, and unlikely ? must find a way to unite the natives, capture the goddess, and end lifetimes of war.