Melanie Gate, a foundling with a peculiar talent for opening the unopenable, agrees to accompany a gearling automaton named Traveler on his quest to find a home, only to be pursued by the most dangerous wizard in the land and, along the way, discover her true powers.

The evil wizard Maldred has stolen the gold and silver keys which will allow him to release the Naga, the powerful earthquake dragon at the center of the earth--so Drake and several of the other Dragon Masters travel to the Naga's Temple in the Dragon Islands, to try and stop Maldred, and prevent him and the earthquake dragon from destroying the kingdom.

In their third trip through the enchanted library, Cleo and Evan land in "The Werewolf's Curse" where Evan is promptly bitten by a werewolf, and the two need to find the cure--and the next key--before the full moon rises and Evan becomes stuck in this horror story forever.

Neither Cleo nor Evan like the new school librarian, Ms. Crowley, but they're very curious about where she disappears to at the back of the library, so one day they follow her--and find a secret door, a magical library full of locked books, and a letter from the previous librarian telling them that she's trapped somewhere between the covers of one of the enchanted books, and they must travel through the stories in order to save her.

This time Cleo, Evan, and Ms. Crowley (who, it turns out, is the missing Ms. Hilliard's sister) find themselves in a confusing fantasy book, caught up in a war with wizards, elves, trolls, and the mighty Golden Dragon-- and while they manage to find their missing librarian, their quest does not end there.