The story starts out on a little farm cabin in Vermont. The Worthens are attacked by a bear when it stumbles into their cabin. Lyddie bravely defends her family, but her unstable mother, Mrs. Worthen, is sure that Judgment Day has visited them all, and quickly whisks her two youngest children, Agnes and Rachel, off to her sister's farm. Lyddie and Charlie, her brother, are left behind to fend for themselves. Later on, Lyddie is informed by her mother that she and Charlie are now responsible for the debts their late father incurred while he was alive.
Lyddie becomes a servant at the Cutler tavern and subsequently works at the Concord Corporation mill in a courageous bid to save the family farm and to reunite her siblings again. She is resourceful, tenacious and hard-working; in fact, she is so single-minded that she is not willing to admit to herself that she has become a slave to her goal. She begins to change her mind about her slave status at the mill when she is forced to face the reality of her situation: there are no safety measures put in place for mill workers and many accidents happen; also, mill workers endure dehumanizing work conditions and long workdays at low pay. Lyddie herself is torn about signing the petition for a 10 hour work day (mill workers work 13 hours) as she makes more money with added hours.
It is Mr. Marsden, the overseer, who decides Lyddie's fate at the mill. After befriending a young girl, Brigid, Lyddie is happy to treat her as a sister; bravely, she comes to the defense of the helpless girl when Mr. Marsden makes an unwelcome sexual advance towards Brigid. Incensed that Lyddie has the gall to stand in the way of his desires, Mr. Marsden has Lyddie fired for being a "troublemaker." Lyddie tries to defend herself, but cannot answer Mr. Marsden's charge that it is her "moral turpitude" which has caused her to be a thorn in his side. Embarrassed that she does not understand what "turpitude" means, she is unable to mount a credible defense. She is fired without an honorable discharge certificate, which makes it virtually impossible for her to be hired at any other mill. This is why Lyddie goes back to the farm.
She tries to get her old job back at Cutler's Tavern, but is told that the position has been filled. Lyddie makes her way back to her old home. Luke Stevens, the neighbor's son, asks her what her future plans are (we find out that the Stevens family have bought the farm). He proposes marriage, but Lyddie politely declines. She vows to go to college and promises herself that she won't "come back weak and beaten down and because I have nowhere else to go. No, I will not be a slave, even to myself."
We get the idea that she will be back on her own terms when she has succeeded in her goal to be self-reliant. Likewise, the novel intimates that she will eventually accept Luke's proposal when she has overcome the demons of her past and is able to decide her future, independent of what others may have decided for her. So, her journey back to the farm represents a full circle journey of self discovery and self awareness. Armed with the knowledge of what she really wants out of life, she is able to go forth confidently to realize her dreams.
Hope this helps. Thanks for the question!