Sass and Traz Save The World is Book 3 in The Library Series.
 
Sass and Traz find themselves stuck in a library with a muddle headed knight, a fire breathing dragon and a magical box full of cards. They thought that puzzling pirates, speaking with a genius and rescuing a damsel in distress was difficult, but this time the future of the whole world is at stake. This time, they need to help Ms Burns understand the magic of the library and uncover her real destiny.