Three wizards have moved into Rebecca's district with nasty hobgoblins in tow. Why are they so helpful, giving free bags of potatoes to everyone? Rebecca finds out the tainted potatoes keep all that eat them under the spell of the wizards.

Rebecca and the house goblins struggle to destroy the potatoes, but the wizards are busy planting more of the horror harvest throughout the districts. Nearly everyone is now under their control. Rebecca is helped by the three old sisters and a bridge troll to take back the districts from the dangerous wizards.