V.C. Andrews' Dollanganger Saga If There Be Thorns

Cathy Dollanganger lives together with her husband Christopher and his two sons, Cathy's sons who are unaware of the incestuous nature of their parents' relationship. When a mysterious woman moves in next door and befriends the younger boy, Bart, he begins to display accusatory behavior towards Cathy and Christopher. Heather Graham plays Corrine, Bart's grandmother, whose true identity is revealed to be the family's long-hidden secret. The film follows the tragic climax as all of the family's secrets are exposed, leading to a devastating conclusion for the family.