The most dangerous evil has infinite subtlety and patience. Beware: It is rising.
At the end of the school year, Kendra and her brother, Seth, find themselves racing back to Fablehaven, a refuge for mythical and magical creatures. Grandpa Sorenson, the caretaker, invites three specialists—a potion master, a magical relics collector, and a mystical creature trapper—to help protect the property from the Society of the Evening...

Danger lurks everywhere.
Strange things are afoot at Fablehaven. Someone or something has released a plague that transforms beings of light into creatures of darkness. Seth discovers the problem in its infancy, but as the infectious disease spreads, it becomes clear that the preserve cannot hold out for long.
In dire need of help, the Sorensons question where to turn. The Sphinx has always given sound advice—but is he a traitor?...