The magical preserve Fablehaven provides refuge to numerous mystical species: centaurs, trolls, satyrs, ogres, fairies, minotaurs, brownies, imps, nymphs, and many others. But some beings are too large and powerful to be confined to regular enchanted refuges. These mightiest of creatures dwell inside the dragon sanctuaries.

When the goddess Artemis disappears while hunting a rare, ancient monster, a group of her followers joins Percy and his friends in an attempt to find and rescue her before the winter solstice, when her influence is needed to sway the Olympian Council regarding the war with the Titans.