When the Grace children go to stay at their Great Aunt Lucinda's worn Victorian house, they discover a field guide to fairies and other creatures and begin to have some unusual experiences.

With goblins, trolls, and the house boggart all trying to get them, the Grace children turn to Great Aunt Lucinda for help.

When Mallory and Jared attempt to rescue Simon from goblins, they use a magical stone which enables them to see things that are normally invisible.

After Mallory is kidnapped at her fencing meet, Jared and Simon search for her near an old quarry and find themselves amidst dwarves and goblins.

The Grace children square off against an evil ogre who has kidnapped their mother and enlist help of a brownie, hobgoblin and more in their quest to reunite their family.

Eleven-year-old Nicholas Vargas's life is turned upside-down when his father remarries and moves him and his new family to Florida; but when an expedition to a nearby lake turns up a little nixie, Nick, his brother Julian, and step-sister Laurie have to figure out a way to stop a horde of rampaging giants.