Don’t jump to conclusions!

That’s the advice given to Constable Stalker (Saoirse Ronan) by Inspector Stoppard (Sam Rockwell) as the two investigate the murder of an American director backstage at the hit play The Mousetrap in See How They Run, which opened Friday for Searchlight Pictures.

The movie is set in London’s West End in the 1950s, where The Mousetrap the play was opening to packed houses daily. (The play went on to set an almost unbeatable record for longevity; it opened in 1952 and ran continuously through 2020, when Covid shut it down for about a year before it resumed its run.) The movie uses several real-life actors from the initial run of The Mousetrap as its characters.

In the film, the drunken, womanizing director, Leo Köpernick (Adrien Brody), who was hired to shepherd a film version of the popular stage play based on one of Agatha Christie’s most famous stories, is killed in the costume shop as he searches for a new outfit to replace the one he ruined by fighting Dickie Attenborough (aka Sir Richard Attenborough, played by Harris Dickinson) who was starring in The Mousetrap. Köpernick had been flirting a little too aggressively with Attenborough’s wife, Sheila Sim (Pearl Chanda), and Dickie responded with violence.

Shortly thereafter, Köpernick is brained with a sewing machine, and his body ends up posed on the stage, with an extra gruesome touch: the killer tried to cut out his tongue.

This brings Stoppard and Stalker to the theater, to interrogate the cast and crew backstage to determine which of them (if any) are responsible for the murder. As this is a whodunnit, there are of course a plethora of suspects, and all of them seem to have a motive that would make them want to off Köpernick.

There’s the disgruntled screenwriter, Mervyn (David Oyelowo) whose script Köpernick literally ripped in half, wronged husband Dickie, John Woolf (Reece Shearsmith) the producer who would benefit if the play were to close, and the hard-nosed theater owner (Ruth Wilson), who would not benefit if a movie of the play (and it’s famous twist ending) was seen by all.

Everyone is suspect, even Inspector Stoppard, to Constable Stalker (who needs to be reminded to not jump to conclusions), who is trying to be taken seriously as a policewoman at a time when sexism was rampant. Stalker approaches the case with a dogged eagerness, putting her at comedic odds with Stoppard, who is much more laid back in his methods (or in other words, his character is more often than not inebriated.) A second murder leads to more confusion and increased pressure to solve the case.

Much like how the movie Scream explained the rules of being in a horror movie to the characters attempting to survive a horror movie, See How They Run has its meta moments as the late Köpernick, mostly in flashback, explains the rules of a whodunnit even as he expresses is desire to subvert them. (His character does explicitly delineate the ending of the movie as he does so, though without disclosing the identity of the murderer.)

Not that it’s hard to figure out who the killer must be – but as the movie takes pains to point out, there’s a lot more to the story than just knowing whodunnit. The story and the performances are paramount both on stage and in the film. Ronan and Rockwell are standouts in this regard; Stalker’s daffy enthusiasm is tempered by a quick wit and Stoppard’s dissolute demeanor hides a deep sadness that Rockwell slowly reveals throughout the movie.

See How They Run is a fun homage to Christie’s play, heavily laden with Easter eggs from her life and works and a brief appearance of the celebrated writer herself in the denouement.