As critic Jan Swafford has pointed out, you know Bach was a genius because his music is impossible to entirely mess up. You can arrange Bach for brass band, vocal group, or Moog synthesizer, and the sheer majesty of the master’s depthless invention always comes through.

The same is true of Agatha Christie, and thus Kenneth Branagh’s new film Death on the Nile totally works on the most basic level. A collection of characters with connections to a wealthy heiress (Gal Gadot, glamorous) assemble on a riverboat to celebrate her marriage to a man with suspicious motives (Armie Hammer). But then, they all have suspicious motives, and suffice it to say that the title is a understatement insofar as it isn’t pluralized.

Branagh’s adaptation of Christie’s 1937 novel, with a script by Michael Green, stars the actor/director as iconic detective Hercule Poirot in a mustache so elaborate, it merits its own backstory - and gets one. The new film is a follow-up to Branagh’s previous outing as Poirot, 2017’s Murder on the Orient Express. Green also wrote that screenplay, with a similar approach: tweaking Christie’s characters to fit 21st century sensibilities, while preserving the essential setting and plot.

In the earlier film, the gambit worked splendidly. Here, the approach starts to show its strain. The preview audience I caught the movie with were clearly looking for some escapist entertainment, and weren’t necessarily thrilled that Branagh cut off a few of their escape routes.

For starters, it might be jarring to see Hammer in a starring role. Since principal photography wrapped in 2019, Hammer has essentially been dropped by Hollywood in the wake of shocking abuse allegations. The film’s promotional campaign understandably doesn’t highlight Hammer’s presence, so fair warning: if you go to Death on the Nile, you will see Hammer onscreen as part of a jealous love triangle. Do with that information as you will, and if you want even more information on what the film’s stars have been up to since Branagh snapped his clapboard - it’s understandable if you don’t - you can read why the film has become “every publicist’s worst nightmare.”

Then, there’s an awful lot of Hercule Poirot in this movie. Branagh and Green are betting on audiences being intrigued by the detective’s backstory, which we learn here involves a tragic loss and a wartime injury. I wasn’t hugely intrigued, and would much rather have seen an exploration of the ambiguously gay-coded elements of Poirot’s life than be subjected to a dreary flashback to an extremely boring heterosexual romance. (There is a gay relationship between two other characters in Death on the Nile, but unfortunately it’s almost as boring.)

One of the production’s most intriguing decisions is to re-imagine the character of novelist Salome Otterbourne as a singer, played by Sophie Okonedo with an act very specifically inspired by the guitar-slinging Sister Rosetta Tharpe. Okonedo lip-syncs to Tharpe recordings, which sound great and add welcome musical gusto to the proceedings; the homage will surely attract new ears to Tharpe’s music, though the complete recontextualization of her pathbreaking work is a peculiar choice for a film released during, of all times, Black History Month.

But back to the Bach analogy, it’s hard to go entirely wrong with this cast and this source material. Annette Bening glories in the role of plein air painter Euphemia; Rose Leslie is compellingly nerve-wracked (wouldn’t you be?) as a maid who sees what she oughtn’t; and Emma Mackey is positively smoldering in the role of Hammer’s jealous ex. Letitia Wright, who plays Salome’s niece, is deeply humane in an underwritten role.

The movie is so much fun when it’s trying to be that audiences may have a hard time following it into the depths it tries to plumb. At the screening I attended, viewers were audibly impatient during a long, climactic silence: the film simply hadn’t built the head of dramatic steam to justify such a bold gesture on the part of director Branagh, who hasn’t seemed to realize he’s not doing Shakespeare any more.

One wonders what Euphemia would make of Haris Zambarloukos’s gauzy cinematography, which places the characters in a scenic fantasia of ancient Egypt between the wars. It’s attractive but arid, a disappointment given that we have plenty of Marvel and Star Wars movies to transport us to CGI fantasy worlds. The Nile is a real place and, however deadly it might be for Christie’s victims, it would be nice to visit.