Fatal Lessons: The Good Teacher (2004)

Samantha Stephens is a successful illustrator, mother, and wife who seems to have everything. Concerned that her daughter Molly is having trouble in school, Samantha enlists the help of Molly's teacher Victoria in getting her daughter back on track. When Samantha falls mysteriously ill and begins to suspect that Victoria is not whom she claims to be, a series of bizarre revelations lead to a shocking and deadly climax in which only a mother's love can save her family from a terrifying fate.