 Celebrant uses the feast to declare that war against the humans and also reveals that the second of seven dragon sanctuaries has fallen.Now Kendra and Seth must figure out a way to deal with a new deadly enemy, the Dark Unicorn Ronodin, while dealing with their first summer solstice at Wyrmroost.Making matters worse is a cursed castle that could hold secrets to help them or ruin them all; making matters even worse, Knox and Tess learn the secrets of Fablehaven and Knox finds a way to take the two of them to Wyrmroost all while the war is occurring.