The Secret Heart (1946)

Penny Addams lives in a constant state of depression stemming from the trauma of her father's death when she was just a young girl. Her brother, Chase, and stepmother, Lee, work to help Penny process her grief through psychotherapy and revisiting their past, but only the revelation of long-buried family secrets -- including her Lee's secret lover and the true nature of her father's death -- can bring Penny out of her intense despair.