Another Agatha Christie movie, another old-school whodunit that doesn’t measure up to Kenneth Branagh’s amazing mustache.

“A Haunting in Venice” (★★½ out of four; rated PG-13; in theaters Friday), Branagh’s third go-round as ace Belgian sleuth Hercule Poirot (and third time manning the director’s chair), is only marginally better than the previous two stale outings, 2017’s “Murder on the Orient Express” and last year’s “Death on the Nile.” For his newest starry murder mystery, based on Christie’s “Hallowe’en Party,” Branagh challenges Poirot’s deductive mind and supernatural belief system and surrounds him with spookiness that can only spiff up a creaky plot and thin characters so much.

Set in 1947 – 10 years after “Nile” if anyone’s counting – this tale finds Poirot retired and living in Venice, Italy. After a career of seeing the worst of humanity while solving murders and witnessing the horrors of war, the ex-detective is content gardening, hiding from potential clients and waiting for his pastry delivery (like a post-war Postmates).

“Cakes for cases,” Poirot’s friend Ariadne Oliver (Tina Fey) teases him when she comes to visit. The world’s top mystery writer is in Venice to attend a Halloween seance held at a supposedly haunted palazzo, which was once an orphanage but is now said to house the spirits of tortured children.

The palazzo's owner is opera star Rowena Drake (Kelly Reilly), a soprano who hasn’t sung a note since her ill daughter Alicia suffered a broken engagement and bizarrely took a header into a nearby canal, and she’s hired renowned psychic Joyce Reynolds (Michelle Yeoh) to hold a gathering to communicate with the dearly departed.

Knowing Poirot will think all this is hooey, Ariadne convinces him to come along and debunk the “Unholy” Mrs. Reynolds as a charlatan. But a long and twisty night kicks off in murderous fashion: One of the guests winds up dead, the survivors are trapped by a nasty storm, and Poirot gets back to what he does best, though our hero is thrown off his game when he starts to see and hear strange things.

An intriguing lot rounds out the suspect list, including “Belfast” co-stars Jamie Dornan and Jude Hill as a doctor suffering from post-traumatic stress disorder and his clever son, Kyle Allen (“West Side Story”) as Alicia’s ex-fiancé and Camille Cottin (“Stillwater”) as Rowena’s loyal housekeeper. Fey’s Ariadne is the only supporting player that really pops, as a wry foil to the reserved Poirot. The detective himself gets another decent fleshing-out from what Christie had on the page courtesy of Michael Green’s screenplay, which takes more freedom with the source material than "Orient Express" and "Nile" did with their better-known tomes.

Like Branagh’s previous mysteries, “Venice” is awfully nice to look at and Oscar-winning "Joker" composer Hildur Gudnadøttir's darkly classical score sets a pleasingly creepy vibe alongside masked Italian gondoliers and costumed kids. Yet aside from Yeoh’s character and the occasional odd figure in a mirror, it’s not nearly as scary as it should or could be – the family-friendly “Haunted Mansion” is more unsettling, honestly – and the narrative is a grind to get through before Poirot finally reveals all.

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The main problem with these throwback Christie adaptations is that, while sufficiently stylish and serviceable, they just don’t have the infectious, go-for-broke energy of a “Knives Out” movie or even a more relatable version of a classic literary sleuthing type like the “Sherlock” TV series. Multiple bodies drop dead, Poirot’s facial hair is still on point, but “Haunting” can’t exorcise ghosts of the past enough for a thrilling case.