Who is Marie Pye Morrision from Crow Lake and what is their importance?

Marie Pye is Laurie's oldest sister. Marie is a shy and quiet young woman who is infatuated with Matt Morrison. Katie recalls Marie coming by the house many times after their parents' funeral to speak to Matt. After Laurie's death, Marie takes up the slack on the farm and begins working in the fields beside her father. This leads to Marie and Matt being thrown together quite often as Matt works on the farm as a hired worker. In the end, Marie and Matt become lovers, resulting in a surprise pregnancy. When Calvin learns Marie is pregnant, she runs to Matt and tells him how her father killed Laurie and she is afraid he will kill her too.