From Redwall Abbey, Warbeak and her Sparra squadrons fly South bearing the Riddle -- they hope to find Matthias and help his quest. But they are unaware their departure is observed by Ironbeak, an evil raven general who invades Redwall as soon as Warbeak is gone. They drive the Redwallers into the Cavern Hole, making them prisoners in their own abbey. Slagar and his slaves ascend the huge Great South Cliffs and cut off the means of pursuit leaving Matthias unable to follow. They pass through the forest and survive an attack by the fearsome and terrifying Painted Ones - only to find that Slagar is about to cross a huge river, beyond which a huge rat army awaits him and his slaves. Mattimeo is beyond help, Matthias is halted - and Redwall is under siege.