PHOTO BY ROB YOUNGSON / 20TH CENTURY STUDIOS

Kenneth Branagh’s Hercule Poirot is invariably shot at odd angles in “A Haunting in Venice,” the third of the actor/director’s Agatha Christie adaptations. The camera leers at him from above or lingers too close on his searching face, never affording him the straightforward depiction the rest of the cast receives.

Is it a gothic flourish, inserted to signify that we’re in the realm of horror? Is it a symbolic representation of a character searching for his true self — as frequently pointed out by the mystery writer (Tina Fey) urging him to return to detection? Is it a hint at a revelation to come?

Your interpretation may vary — or you may not notice such details at all, instead finding yourself swept up in a pleasant and fast-moving mystery. “A Haunting in Venice” is in some ways the least ambitious of Branagh’s three Poirot tales; I was shocked when he began his whodunit speech barely 80 minutes into the film. The number of characters are manageable and the twists are restrained. Rather than resulting in a thin story, though, those constraints make this film perhaps the most easily enjoyable of the trilogy; it’s not a cinematic triumph, but it is a satisfying and spooky yarn.

Poirot is attempting a Venetian retirement, whiling away his days with rooftop siestas and a constant supply of pastries. When writer Ariadne Oliver (Fey) calls in a favor, however, he’s drawn to a Halloween party featuring a somber seance; a young woman has plunged to her death from a supposedly cursed building, and a world-renowned medium (Michelle Yeoh) has agreed to try and make contact.

Poirot shows up hoping to debunk the claims of mysticism — inevitably, however, a body or two is found and the detective locks the doors to unravel the mystery.

Even in a more melancholy mode, Branagh clearly has a great time with the character; Fey fits in very nicely, bringing a wry attitude that complements Poirot’s deadpan. Yeoh, too, stands out; this is no post-Oscar cash grab but a project she’s clearly invested in.

Horror is sprinkled atop the script in familiar forms — a mirror scare here, a disappearing figure there — to give this mystery a macabre tinge, but this is no giallo or ghost story. It is a satisfying potboiler with the right amount of fright; call it a perfect September movie, inching toward spooky season without going for the jugular.

My Rating: 8/10

“A Haunting in Venice” is now playing in theaters.