On the way, however, they learn that the Marlfoxes will attempt to seize Redwall, and hasten onward to warn them, while Guosim from another part of Mossflower do the same.

The Marlfoxes command a vast army of water rats, and they travel around the country seeking rare and priceless artifacts.

The Marlfoxes, backed by an army of water rats, mount a successful invasion of Redwall and steal the tapestry of the long dead hero, Martin the Warrior.

Three young Redwallers, Songbreeze Swifteye, Dannflor Reguba, and a Guosim shrew named Dippler set out after Mokkan, trying to retrieve the tapestry.

They meet Burble, a water vole, and have many adventures and meet many friends who help them on their journey, such as the gigantic hedgehog Sollertree, who lost his daughter Nettlebud to the Marlfoxes and water rats, and the Mighty Megraw, a large osprey who used to live by the Marlfox island but was driven away in an ambush by magpies.

The surviving water rats are left on the island to become peaceful creatures and farm the land, and the companions return home to Redwall, where Songbreeze Swifteye is named Abbess and Dannflor Reguba is named Abbey Champion by Cregga Rose Eyes, Redwall's blind badgermum.