Elizabeth Harvest movie plot

After Elizabeth married the scientist Henry, they lived in the latter's mansion. Henry generously gave money, jewelry, and high-level dinners. Everyone else treated Elizabeth with humility, but she always had a lingering sense of unease. Henry assures Elizabeth that everything he owns is hers now, except for a locked room that is not allowed to enter. After Henry's business trip, Elizabeth decides to find out the truth on her own, and discovers that she might not be what she thought she was.