Raine, Countess Spencer. For years, Princess Diana looked at her as the wicked stepmother who stole the affections of her father and brought chaos to her ancestral family home. However, it would be "Acid Raine" who Diana turned to when her marriage to Prince Charles went into free fall. What caused this change of heart and what new insights does it reveal about the shy, guarded princess? Through archival footage and interviews with family friends and confidantes, we explore this little-known part of Diana's story.