Heirs to Manilius. The Warren Brood, #4

"Do not worry, Lily. As sure as the moon rises, we shall find you." After travelling halfway across the universe and defeating the enigmatic Weeping Man, half-spider Spinneretta was looking forward to getting her normal teenage life back. Instead, she finds herself setting off on one last adventure to help Mark find his missing cousin Lily, who was last seen fleeing the ruins of Arbordale with a dangerous cult artifact six years ago. Compared to all the nightmarish trials the Warren brood has overcome before, finding a missing twelve-year-old girl sounds almost like a vacation.
But the discovery of a trail of ritual killings turns their victory lap through New England into a frantic race against time. Someone from the moon-cursed Lunar Vigil survived the fall of Arbordale, and they've now come seeking Lily and the Key to Manilius for their own nefarious ends. With a forgotten grimoire on the loose, moonlight terror driving the towns of Balsam and Peyton to the edge of madness, and a dead Primal One's unrealized plans still in motion, even the Yellow Princess and the Chosen of Y'rokkrem will have their work cut out for them.
And in the very center of this storm of crises stands Lily, a broken girl harboring a power she doesn't understand. With the Key to everything in her hands, will she put the story of the Lunar Vigil to rest forever, or will she fall victim to the Heirs to Manilius? Book IV of the Warren Brood series.