After the Deluge(1968)

Patricia (Mijanou Bardot) is a wealthy party girl who is bored with her jet-set lifestyle and friends. She gets in her car and drives off into the mountains in search of a new thrill. When two men wreck and burn her car, she joins them in their mountaineering life. She sleeps with one man, but jealousy ensues and she leaves for swinging London town with the other man. Eventually the men end up back in the mountains as the profoundly disturbed Patricia packs a loaded gun and goes after them both.