Based on the popular novel by V. C. Andrews, Flowers in the Attic centers on such chancy topics as incest and misguided religiosity. When their father is killed, teenagers Cathy (Kristy Swanson) and Chris (Jeb Stuart Adams), together with their preteen siblings Cory (Ben Ganger) and Carrie (Lindsay Parker), are put in the care of their religious-zealot grandmother (Louise Fletcher). Grandma has never approved of the wanton lifestyle of the kids' mother Corinne (Victoria Tennant), and she has no intention of extending her love to the children. Even worse, Corinne is anxious to win back the love of her estranged father, who, knowing that Corinne and her late husband were cousins and thus incestuously linked, would never approve of any children from this union. Thus, the four children are locked in their grandmother's attic, far from the view of their unforgiving grandfather. How the kids cope with their imprisonment is the heart of the film.
~ Hal Erickson, All Movie Guide