Redwall - Season 1 Episode 12 Underground

As Matthias is lost in Asmodeus' caverns, Cluny digs his way under Redwall, taking advantage of the exhausted citizens of Redwall. After using the sword to escape the caverns, Matthias and the shrews go on a terrifying river adventure and he returns with the shrews to defend Redwall - but not before he is almost trapped by Cluny and only just saved by Cornflower. Cluny flees at the sight of Martin the Warrior's "ghost" while Matthias at last gets to wear his hero's armor.