From the Publisher: Enslaved by the evil ferret King Agarno and his daughter, Princess Kurda-slavers who have shackled hundreds-the brave squirrelmaid Triss, along with Shogg the otter and Welfo the hedgehog, plans a daring escape by sea. In her flights, Triss happens upon Redwall, and the abbey creatures discover a new hero in her. Someone brave enough to carry the sword of Martin and face the evil that threatens them.

Book 1: Season of runaways -- Book 2: Of serpents and paradoxes -- Book 3: Swordmaid.