Thunder on the Hill is a British-set American 1951 Film Noir-esque murder mystery film, based on the British play Bonaventure by Charlotte Hastings. It stars Claudette Colbert and Ann Blyth, was written by Oscar Saul and Andrew Solt, and was directed by Douglas Sirk.
Somewhere in Norfolk, England, a town is forced to shelter inside a convent hospital ward due to flooded homes, headed by Sister Mary Bonaventure (Colbert). Within the crowd is convicted murderess Valerie Carns (Blyth), who has been sentenced to death for poisoning her famous pianist brother Jason.
Fortunately, the rain has postponed the execution, but Sister Mary is convinced that Valerie didn't poison him and tries to play detective herself in order to solve the mystery, with the help of Valerie's fiance Sidney (Philip Friend), other nuns, Dr Jeffreys and his sick wife Isabel, and the caretaker Willie, much to Mother Superior's annoyance.
- Amateur Sleuth: Sister Mary, in order to work out who actually murdered Valerie's brother.
- Character Title: An alternate title for the movie (and the actual name of the play) is Bonaventure, which is Sister Mary's surname.
- Chekhov's Gun: Sister Josephine's The Sunday Times collection.
- Chekhov's Gunman: Willie.
- Comic-Book Time: There is no clear date for the film, apart from being set in an era where the death penalty in the UK is in full force.
- Disability as an Excuse for Jerkassery: Valerie's brother became ill and treated his sister Valerie terribly when she was caring for him up until his death. This is the biggest reason why she was sentenced to execution.
- Film Noir: Although there are no common character archetypes that fit with the genre, the film was marketed as one. However, there is a definite "whodunnit" scenario and everyone involved had a guilty conscience.
- Hollywood Nuns: All the nuns on screen, for definite. From the "penguin" suits, to the main nun character being called Mary.
- Just Following Orders: Because Valerie has already been sentenced to death, the police that have been sent to watch her have no intention of furthering the investigation. When Sister Mary gives them decent evidence, they ignore her, claiming that it's because she's a nun.
- Police are Useless: Related to the Just Following Orders above, the police that are watching Valerie don't bother to listen to Sister Mary whenever she brings them evidence to prove Valerie's innocence.
- Tsundere: Valerie. Understandable, because she's about to be executed for a crime she didn't commit.