There are several significant elements in the opening scene of Donnelly's A Northern Light. Clearly, the mystery of the dead woman sets the mood for the story, especially in contrast to the beautiful day Mattie describes. She tells herself:
Nothing bad can happen at the Glenmore, not on such a day as this.
However, there are other things that Mattie speaks of that provide foreshadowing that encompasses not just what will be discovered about Grace Brown's death, but also about change—it's in the air, creeping toward her, and the reader is prepared that this will impact Mattie greatly.
I'm not scared, not exactly, but I can't explain how I feel. Words fail me sometimes...Right now I want a word that describes the feeling you get—a cold, sick feeling deep down inside—when you know something is happening that will change you, and you don't want it to, but you can't stop it.
These comments alert the reader to the impending alterations in Mattie's world. She has never felt this way before, but she knows something is approaching—something that will not only change her, but will define who she is and will impact her choices—and what happens in her life. Mattie credits Miss Wilcox, her teacher, with instructing her about many things; she only wishes her teacher had told her how to handle a situation like this one.
Change will not only come because of the way Mattie and Grace are inextricably now joined (in that Mattie has a packet of Grace's letters—letters Mattie had agreed to destroy...at least before Grace's death under what become questionable circumstance). Mattie will be searching for the truth of Grace's death. Change will also occur in Mattie's life with regard to her schooling (her hope to attend college in New York), her relationship with Royal Loomis (who does not fit into her college plans), and whether she will stay in the town where she was raised or move out to pursue her dreams.