A message by Sir Thornberry lures both the Gummis and Igthorn back to Ursalia, where a new band of Gummies, the Barbics, have taken refuge. The new tenants, however, are mostly a rather unsociable bunch with a deep hatred for all humans. They seek the ultimate weapon in Ursalia to get revenge against the humans. And as it so happens, this weapon is close to falling into Igthorn's hands.