The Good Mother (2013)

When troubled teen Jillian is arrested and her mother is missing, she is taken in by the well-respected family of her best friend, Melanie. She starts to rebuild her life, but when Melanie dies after a long illness, Jillian discovers that Melanie's mom might not be "The Good Mother" we think she is. Now her younger sibling is starting to have similar symptoms and Jillian must fight to find out the truth, save the life of the young child, and face the fact that the only mother figure she has ever known just might be a murderer.