Answer:
In the climax of the book, Mr Mardsen said that she was a troublemaker and Lyddie denied these complains, he did it again and was fired from the mill.
Lyddie is helping new girls get used to the factory life. She also sticks up for Brigid by dumping a bucket of water on her boss, Mr. Marsden when he tries to becomes inappropriately romantic with Brigid. Mr. Marsden gets Lyddie fired by saying that she has a problem with moral turpitude. This basically means that she is immoral, but since Lyddie does not know what the word means she cannot defend herself. This is a turning point for Lyddie because when she is fired she makes it a point to better educate herself. Since she is not granted a certificate of honorable discharge, she cannot get another job at a mill.