Rise of the Teenage Mutant Ninja Turtles - Season 1 Episode 35 -

The Turtles plumb the depths of a mysterious hidden library in search of a way to rescue Mayhem from within April's mirror. While trying to be quiet, they must also evade not having a sound heard by the Bat Librarian's Hush-Bats and contend with the Foot Lieutenant and Foot Brute.