Take an exotic setting, populate it with strangers who are not what they seem, add one or more murders and mix in plot twists, distracting tangents and plausible explanations that prove false.
Of course at the end there's an "aha" moment of clarity from a hero who reveals the murderer's identity.
So formulaic is the "whodunit" it has inspired parodies dating back to when Arthur Conan Doyle and Agatha Christie were still shaping the genre.
One recent spoof is Ed Sala's Bloody Murder, which Hutt Repertory is presenting.
Sala, answering questions by email from his home in the United States, said his publisher described his play as a comedy/mystery, "but I feel its primary appeal is as a very odd British mystery story".
It has been performed in cities all over the US and he is delighted its first outing in another country is to be in New Zealand.
A group of the usual British murder-mystery types gather for a weekend at the country estate of Lady Somerset. Suddenly, one of them dies, poisoned.
Her Ladyship (to be played in the Hutt Rep production by Zen Neilson) refuses to summon the police. She says she doesn't want go through all this again.
All what again? And why were all the guests invited here in the first place?
But this is not another formulaic mystery story. It's more like Agatha Christie meets Pirandello, as the characters rebel against the author and refuse to be killed off.
Sala says he wanted to write a piece that explored the similarities in plot lines and characters in so many British murder-mystery books.
"The characters in a writer's piece, and often several elements of the plot, shout out against what the writer is trying to do.
"[The writer tries to avoid the] too obvious, too simplistic. But it often feels to the writer that the characters themselves are arguing with him, saying 'I would never do that,' or 'I simply refuse to do that or anything else you might want me to do'.
"It's a little creepy, sometimes."
Sala's master's degree from Virginia Commonwealth University was in play writing but he found it was easier to be hired as an actor than to try to sell plays to the public.
"And maybe my plays weren't very good. But Bloody Murder has proved far more popular with audiences than my earlier works. It's got a gimmick that works.
"Plays with gimmicks - a unifying concept that catches the audience's attention and makes it fairly simple for the playwright to write the play around this one idea - are generally criticised as being a little too easy for the writer or as a one- themed concept.
"But the gimmicks seem to work well in this show.
"At their best, they surprise the audience. The show has been reviewed as having many effective twists and turns," Sala says.
Hutt Rep is billing it as "diabolically different".
"The playwright's obvious love of murder mysteries allows him to call attention to and play havoc with its quirkiest conventions."
Doug Buchanan, well known to Hutt theatre- goers for his award-winning productions of Unseasonable Fall of Snow, Billy Liar, and last year's moving Wednesday to Come, is directing.
What: Bloody Murder by Ed Sala
Where: Theatre 108, 108 Oxford Tce, Epuni
When: November 28 to December 8, 8pm, matinee only December 1 and 2, at 4pm.
No performance December 3.
Tickets: $20 adults, $18 seniors and students. Bookings, 939 7529.
- Hutt News