Redwall Abbey, inhabited by peaceful monk-like mice, is set in the heart of Mossflower Woods and is the center of life for all the peaceful creatures who inhabit the woods. In this story the abbey is besieged by evil sea rats with an infamously merciless huge rat, Cluny the Scourge, as their leader. The rats are unable to conquer the abbey at first fight and thus infuriated, Cluny is all the more determined to have Redwall Abbey as his own. The rats attack the abbey with various battle plans and finally enter the abbey through the betrayal of a field mouse.