What is the setting of Ellen Foster and the tone?

While I can't write a book report for you, I'll be happy to assist you with the setting and tone of Ellen Foster.  Overall, the novel occurs in the South, specifically in North Carolina.  The year is 1971 -- by the end of the novel, when Ellen is living in a foster home and has therefore named herself Ellen "Foster," it is Christmas of 1971.

When Ellen "speaks," or narrates, it is evident that she is a Southern girl with a sarcastic, yet endearing attitude.  She endures many traumatic events and moves (her father's abuse, her mother's death, living with incompetent/uncaring relatives, etcetera), but her distinctively humorous and mature tone helps make her an endearing protagonist.  The opening sentence of Ellen Foster, "When I was little I would think of ways to kill my daddy" (1), is definitely not a humorous sentence, but one that immediately informs the readers that this narrating girl is not here to play.  Later in the novel, when Ellen has to move in with her grandmother, or her "mama's mama," Ellen makes the comment that "[h]er power was the sucking kind that takes your good sense and leaves you limp like a old zombie" (68).  Quotes like this one are where we see more of Ellen's personality as a likeable narrator who makes even unpleasant situations bearable -- and sometimes even humorous.  Later, as her grandmother is dying, Ellen whispers in her grandmother's ear:

It would humble you I whisper to her sleeping if you for one time stood by something stronger than yourself.  (79)

Here, all of Ellen's past humor is gone, and she emerges with an extremely profound statement, especially considering Ellen is only ten years old at this point.  In this scenario and in others (such as in her mother's death, when she remains at her side, even after she stops breathing), we as readers can fully grasp Ellen's astounding maturity.

Ellen Foster is one of those novels that serves as an excellent example of how setting and tone contribute to overall plot.  We can "hear" Ellen's Southern accent when she narrates, which sometimes makes her narration grammatically incorrect (e.g. "[...] a old zombie"), yet Ellen is a brilliant narrator.  We immediately detect, because of the nature of her narration, that Ellen is a very strong-willed character, yet we also realize that determination, for her character, is both a strength and a weakness (she almost matures too quickly and doesn't get to experience what we might call some of the "joys of childhood").  Overall, the Southern, rural setting of this novel, as well as the distinctively humorous and mature tone of this novel, drive the plot.