[3] Based on the 1967 novel Endless Night by Agatha Christie, the plot follows a newlywed couple who feel threatened after building their dream home on cursed land.

This was the last project on which Sidney Gilliat and Frank Launder worked together for British Lion Films, their home since The Happiest Days of Your Life (1950).

Michael Rogers is a wistful and aimless young aspiring photographer working as a chauffeur and living with his mother in London.

Through his travels as a chauffeur, he discovers a spot along the Devon coast known as Gypsy's Acre, where a dilapidated Victorian mansion sits.

While exploring the property, the two encounter Miss Townsend, a mysterious old woman who tells Michael that Gypsy's Acre is for sale, but that it is a cursed land.

Ellie leaves England and embarks on the remainder of her trip through Switzerland and Italy with Greta, her German language tutor who has taken on the role of a personal assistant.

An autopsy suggests she died of unexpected cardiac arrest, but Michael contests this during the inquest, believing there may have been foul play.

This triggers a memory from Michael's childhood, in which he killed his schoolmate by pushing him into a frozen pond and stealing his watch as a memento.

Their aim was to write a cinematic script with a minimum of dialogue and a deliberate ambiguity of style "in the sense you're never really sure what is being said is what is really meant or really being said.

Endless Night is an exception...  Sidney Gilliat is a very experienced director who understands the problems, and he asked me to talk with him and consider what we should do musically at a very early stage.

Although reasonably faithful to the novel, it is "An example of the sort of thing Christie was writing in her later years: moody psychological studies very different from, and not so much fun as, her early thrillers.

"[11] Contemporary critics have noted "Nice performances all around, with special admiration for Oscarsson's role as the dying architect.

"[12] Another review said "It's not a bad movie, with a decent story and cast, but lacks flair; Gilliat – who has a fine CV – had not directed for ten years and you can tell.