A woman is released from an asylum after the shock suffered during the death of her mother.

Young Susan Shelly, suffering from shock and amnesia, is confined to a sanitarium-convent following the death of her mother, Jessica, in a fire. After 3 years Susan returns home to her father, Edward, and his new wife, Francene, Susan's former governess. Francene, who married Edward because she thought he would inherit his wife's total estate, applies pressure on Edward to have Susan recommitted, knowing that her inheritance would revert to Edward should she be declared insane or die before her 25th birthday. Failing this, Francene persuades her lover, Anthony, the caretaker, to help her recover from Susan a valuable necklace once belonging to Jessica and now missing. During a thunderstorm Susan reconstructs the events leading up to the fire in which her mother perished. She realizes that she did steal the necklace and finds it but refuses to give it to Francene, believing in her hysteria that the woman is Jessica. A chase ensues; Francene discovers Anthony calling the police and stabs him to death. Edward joins in the fray and strangles Francene, just as he killed Jessica, and for the same reason, because of her adultery with Anthony. The scene is witnessed by Susan, who, as she did 3 years before, sets fire to the house and departs with her father, happy in the thought that she is the only woman in his life.