Mild-mannered Goody Goblin, scorned by his own tribe for his good manners, is sent by the Good Magician to find a home for a foul-mouthed, insult-hurling bird called Pet Peeve. The errand snowballs into an invasion of Xanth by mechanical marauders from a robot world, forcing Goody to rally dragons, zombies, centaurs, and even fellow goblins, with an unexpected ally in a strong-willed goblin chief. The twenty-ninth Xanth novel turns an outcast's small kindness into Xanth's last defense.
Summary by Loreful, from public sources