Die! Die! My Darling!

In this 1965 British horror thriller, a young American woman named Patricia Carroll is tormented by her former fiancé's deranged mother, Mrs. Trefoile, who blames her for her son's death in an automobile accident. As Patricia attempts to escape the secluded house where she's being held captive, she must confront the fanatically religious and unhinged matriarch, leading to a bloody showdown that ultimately proves fatal for the sinister woman.