‘Death on the Nile’: Juicy Poirot whodunit solves mysteries of a murder and a mustache

When we think of the greatest mustachioed characters in movie history, certain names come to mind: Rhett Butler and Rufus T. Firefly, Charlie Chaplin in a myriad of roles and even the likes of the Stranger in “The Big Lebowski,” Lando Calrissian in “The Empire Strikes Back” and Bill “The Butcher” Cutting in “Gangs of New York.”

Until now, though, I’m not sure we’ve ever seen a movie with an entire Mustache Prologue, telling the origin story of one of the most famous crumb catchers of all time: that stylish and impressive creation gracing the face of Detective Hercule Poirot, portrayed on TV and in the movies through the years by Albert Finney, Alfred Molina, David Suchet, Peter Ustinov — and by Kenneth Branagh in “Murder on the Orient Express” (2017) and “Death on the Nile,” both of which Branagh also directed.

Before we get to the slow-moving but ultimately juicy and satisfying murder mystery in “Nile,” director Branagh and screenwriter Michael Green plunge us into a harrowing, black-and-white prologue set during World War I, where a digitally de-aged Branagh plays a brave, clean-shaven young soldier who — well, let’s just say we learn why Hercule grew that that facial hair and is never, ever shaving it off.

Cut to 1937, with a deadly romantic triangle that ignites in a speakeasy in London and quickly segues to the marvelously appointed luxury riverboat the S.S. Karnak, which has been commissioned by the obscenely wealthy heiress Linnet Ridgeway-Doyle (Gal Gadot) for a honeymoon cruise down the Nile.

Among the guests, nearly all of whom have motive for murder — or could wind up dead:

• Poirot, who was on vacation in Egypt when he ran into his dashing confidante Bouc (Thom Bateman) and Bouc’s judgmental mother, Euphemia (Annette Bening). Next thing you know, ol’ Poirot is being dragged along for a wedding celebration!
• The dashing but sweaty bounder Simon Doyle (Armie Hammer), who was engaged to the seemingly sweet Jacqueline de Bellefort (Emma Mackey) but dumped her for Jacqueline’s best friend, the aforementioned Linnet.

20th Century Studios

• The jazz singer/guitarist Salome Otterbourne (Sophie Okonedo) and her niece/manager Rosalie (Letitia Wright).
• A gentleman doctor (Russell Brand), a wealthy socialite turned Communist (Jennifer Saunders), the socialite’s nurse and companion (Dawn French), a French maid (Rose Leslie) and Linnet’s cousin/lawyer (Ali Fazal).
• Oh, and the jilted Jacqueline, who has become obsessed with Simon and Linnet, is convinced Simon still loves her, has joined the group and is packing a small pistol, greatly increasing the chances of a DEATH. On the NILE.

The production design and the costumes are as lavish and eye-popping as you’d expect, but even though “Death on the Nile” had a bigger budget than “Murder on the Orient Express,” it actually looks less expensive. It almost always feels as if we’re in an enormous tank on a soundstage (as we often are), with the actors competing with CGI backgrounds. As for the murder mystery, some of the supporting players barely get enough screen time or enough of a backstory to be considered serious suspects, but even when “Death on the Nile” skirts the edge of camp, the fastidious and melancholy Poirot is always there to guide us through the rough spots and solve the case in the nick of time.

Always while keeping that elaborate ’stache intact, not a whisker out of place.