Jimmy Sangster's screenplay for "Nightmare" is an excellent contemporary (early 1960s) thriller with Gothic touches. However, the script falters about halfway through when the young heroine Janet, who has been driven almost out of her mind by a series of terrifying events, is removed from the action of the story.
Instead of centering the action of the second half on characters sympathetic to the heroine who might take up her cause, identify the conspirators and bring them to justice - as happens in, for example, "Psycho" - the script reveals to the audience who the conspirators are, and then, until the final scene, makes them the center of the action.
It is asking a lot of an audience to identify with those whose machinations have brought about the committal of a sympathetic heroine, and this may well explain why the second half of "Nightmare" is less gripping than the first - especially as the plot of the second half is a variation on what has gone before, this time with an unsympathetic character experiencing terrifying events. This part of the screenplay also stretches credibility, since it seems unlikely that an antagonist with an alert and cunning mind would not detect a plot which is dividing him from his female accomplice.
The real strength of "Nightmare", however, is in director Freddie Francis' visual flair. A former cameraman/director of photography, using black and white 'scope and obviously influenced by his work on Jack Clayton's "The Innocents", he succeeds in creating a real sense of fear and isolation around his vulnerable heroine.
He achieves this by using the expanse of the 'scope frame, often surrounding Janet with shadows or, in daylight, setting her in a frame devoid of anything or anybody reassuring. For example: when Janet travels home from school, the railway station is almost deserted; we do not see the departing train from which she has presumably just alighted. There are no other cars on the road as she is driven home. As they pass the asylum she dreads, there are no signs of human activity within the grounds. Once back home she is dwarfed by the mansion "High Towers" she has become heir to, and her isolation is compounded by her home being located in remote snow-covered countryside.
Janet's isolation is social as well as physical; ostracized at boarding school in the early scenes, and clinging to a grotesque doll and a small transistor radio, she is never seen with anyone her own age (mid-teens). Her only friend at the school is a sympathetic teacher. At "High Towers" the guardian she dotes on, Henry Baxter, is at least twice her age - as are her other household companions.
In addition to traditional Gothic trappings (heroines wandering dark corridors in flowing night-dresses, candlelight illumination, door handles seen turning slowly and ghostly nocturnal figures) Freddie Francis endows several everyday objects with fearful connotations - Janet's doll, her transistor radio that forever blares out fast jazz, and above all, a birthday cake with lighted candles. The latter becomes a powerful image of dread, since it was on Janet's eleventh birthday the horrific event occurred that started the cycle of nightmares and fear of inherited insanity.
"Nightmare" has a particularly bleak atmosphere: most of the action is set during a harsh winter, the dialogue has virtually no humor and the ending - which should give the audience a sense of satisfaction - is grimly downbeat. This is probably because in achieving justice for Janet, her sympathizers have virtually duplicated the methods of the conspirators and brought about a similar result - a gruesome death and a woman on the edge of madness.
Highly recommended viewing.