In the final book of The Nymph Keepers, Forest struggles with her duties as court herbalist and the expectations of a future queen. Terryn needs her influence to unite the remaining nymphs under one crown and she needs his power to make a better life for her people. Together, they face the rot creeping across Galia's borders into Ireece. Forest and Flint are tasked with discovering the cause and the cure — but answers are difficult to find and time is running out.

In the south, Silic leads the nymphs of the Darkwater against the Herald of the Gods. His heart still belongs to Forest, but his revolutionary ways may lead him too far from her forgiveness. Jay has been captured, and Aleah is suffering the fallout of her alliance with Keelie. They must decide who they'll save, and who they'll serve, as their world is forever changed.