When Aunt Lucinda goes missing, Helen leads the search, leaving Mallory in charge of her brothers at Spiderwick. Jared is obsessed with finding the magical creature he saw in the attic, enlisting everyone's help to set a trap.

A divide between the twins widens as they split up with Emiko and Hatcher to find more pages. Calliope tries to connect with Simon. Bree tries a different approach to fencing, forcing Mallory to get out of her head and throw a party.

Held captive at Meskwaki, Jared holds his own against the ogre as Mulgarath pressures him for the dragon page. Mulgarath shares his origin story with Jared, trying to show that they're more alike than he thinks.

Mulgarath's plans are coming to fruition as townsfolk either succumb to the sleeping sickness or become the ogre's servants. The gang launches a daring prison raid to rescue Jared. The Grace family must reunite to defeat Mulgarath.