Young mouse Calib Christopher has finally been appointed a squire to the Knights of Camelot. Alas, there is no time to celebrate. His best friend, Cecily, and one of Merlins magical treasures are in the hands (or paws) of the evil Saxons! And its up to Calib and his human companion, Galahad, to stage a rescue mission before its too late, even if it means entering enemy territory.

But nothing can prepare them for what they discover deep within the Iron Mountains. Morgan le Fays magic is powerful and treacherous, and it will test all that Calib and Galahad have learned in their trainingas well as their very allegiance to Camelot.

As the pieces align for the ultimate battle, Calib and his friends will have to harness the magic of Merlin and the strength, bravery, and wisdom within themselves to become the mythical heroes they were born to be.