The following contains spoilers for A Haunting in Venice, which is now playing in theaters.
A Haunting in Venice is the latest entry in Kenneth Branagh's Agatha Christie cinematic universe. The film takes inspiration from the Agatha Christie novel Hallowe'en Party. Just like the film adaptations of Murder on the Orient Express and Death on the Nile, A Haunting in Venice changes many details from the original book. Yet A Haunting in Venice is currently the adaptation that deviates farthest from the original book.
A Haunting in Venice includes many of the original characters from Hallowe'en Party. Yet some of their stories were changed for the film adaptation. At the same time, A Haunting in Venice introduced new characters that don't appear in Hallowe'en Party. And while the essence of most characters stays the same, A Haunting in Venice even made some changes to the final reveal as well.
10 The Séance Never Happens
Hallowe'en Party starts with a party for teenage kids where they play many games, like bobbing for apples or snapdragon. There's even a party game where some of the teenage girls can see their future husbands. However, the party in Hallowe'en Party doesn't include a séance.
A Haunting in Venice brings supernatural and horror elements to the story, yet Hallowe'en Party remains grounded in reality. In A Haunting in Venice, the main characters meet for a séance where Joyce Reynolds tries to contact Rowena Drake's daughter. In Hallowe'en Party, none of this happens.
9 Joyce Reynolds Isn't a Psychic
Michelle Yeoh stars in A Haunting in Venice as Joyce Reynolds. Joyce Reynolds is a renowned psychic whom Rowena Drake hires to try to contact her daughter, Alicia. But in the original Agatha Christie novel, Joyce Reynolds is a thirteen-year-old girl who says she once witnessed a murder.
Joyce Reynolds is one of the guests at the Halloween Party where Ariadne Oliver is also in attendance. While Mrs. Oliver helps the grown-ups set up the refreshments and games, Joyce Reynolds states she once witnessed a murder. However, no one takes Joyce's comment seriously until she's murdered.
8 Alicia Drake Isn't a Character in Hallowe'en Party
In A Haunting in Venice, the séance takes place because Rowena Drake wants to speak with her daughter, Alicia. Alicia passed away after a prolonged illness, and her tragic death still haunts Rowena and Olga Seminoff, who took care of Alicia. Yet in Hallowe'en Party, Rowena Drake doesn't have a daughter.
In Hallowe'en Party, Rowena Drake is a widow who lives alone and hosts many parties and events for the people in the town. Rowena hosts the party for the teenagers of their small town at her home, much like in A Haunting in Venice.
7 Joyce's Death is Different in Hallowe'en Party
In A Haunting in Venice, Joyce Reynolds dies after the killer pushes her from a balcony and Joyce lands on top of a statue. This is a shocking death that everyone in the house sees and sets Hercule Poirot to investigate. But in Hallowe'en Party, Joyce's death is completely different.
Thirteen-year-old Joyce Reynolds dies at Rowena's house, but the circumstances aren't the same. When everyone is playing snapdragon, Joyce is murdered in the room that holds the bowls for the bobbing for apples game. Someone drowned Joyce, holding her head underwater.
6 Nicholas and Desdemona Aren't Siblings
In A Haunting in Venice, Nicholas and Desdemona Holland are half-siblings and assist Joyce Reynolds in her séances. They work the deceptions and tricks that Joyce uses when pretending to contact the dead. Nicholas and Desdemona are trying to save money to travel to the US, hoping to move to St. Louis after watching the classic Christmas movie Meet Me in St. Louis.
But in Hallowe'en Party, there is no Desdemona Holland. Desmond Holland is a character in the book and is friends with Nicholas Ransom. They are two teenagers who were at the Halloween party where Joyce was killed, and Desmond and Nicholas later assist Poirot with his investigation.
5 Leopold's Fate Changes
In Hallowe'en Party, the only character named Leopold is Leopold Reynolds. He's Joyce Reynolds' younger brother. In A Haunting in Venice, the twist at the end reveals he was blackmailing the killer. Leopold blackmails the killer in Hallowe'en Party as well, but with different consequences.
In A Haunting in Venice, the blackmailing allowed Leopold to save a lot of money and pay for bills since Leopold's father struggled after the war. In the end, Leopold agrees to use the money to help the Holland siblings travel to the US. But in Hallowe'en Party, Leopold's end is much darker, as he eventually becomes another victim due to the blackmail.
4 Ariadne Oliver Never Tries to Trick Poirot
A Haunting in Venice provided more detail about Ariadne Oliver and Hercule Poirot's relationship. The film explains Ariadne used Poirot as inspiration for a book, and she claims she's the reason why Poirot is famous. In A Haunting in Venice, Poirot realizes Ariadne invited him to the séance to trick him and use him for another book.
Yet in the Agatha Christie novels, Ariadne Oliver mentions more than once that she doesn't use her friends and family in her stories. She also never tries to deceive the Belgian detective. In Hallowe'en Party, Ariadne Oliver goes to Hercule Poirot for help after the murder of Joyce Reynolds, and the two work together to find the truth.
3 Olga Seminoff's Story Changed Completely
In A Haunting in Venice, Olga Seminoff is one of Rowena Drake's employees and takes part in the séance. She's a nun who fell in love and took care of Rowena's daughter during her illness. In Hallowe'en Party, however, Olga Seminoff has a completely different story.
Olga Seminoff was an au pair girl who went missing before the events of the book. She took care of a rich elderly woman named Mrs. Llewellyn-Smythe, who was Rowena Drake's aunt. Mrs. Llewellyn-Smythe left Olga all her money in her will once she died, but after people accused Olga of forging the will, Olga Seminoff mysteriously disappeared.
2 The Killer Didn't Act Alone
In A Haunting in Venice, audiences find out Rowena Drake is the killer. Rowena killed her own daughter Alicia after poisoning her for a long time to try to keep Alicia away from Maxime Gerard, Alicia's ex-fiancé. But in the original Agatha Christie novel, the killer doesn't act alone.
Rowena Drake was in love with a gardener named Michael Garfield, and they planned the crimes together. Their first crime wasn't the murder of Alicia Drake, since she isn't a character in Hallowe'en Party. Instead, they killed Olga Seminoff to keep Mrs. Llewellyn-Smythe's money for themselves. But after Joyce claims to have witnessed a murder, they believe Joyce is talking about Olga's murder. In desperation, Rowena kills Joyce. This prompts Poirot to investigate.
1 Hallowe'en Party Doesn't Happen in Venice
One of the biggest changes in A Haunting in Venice is the change in setting. The film takes place during a séance gone wrong at Rowena Drake's home in Venice. But unlike the film adaptation, the events of Hallowe'en Party happen in a small English village called Woodleigh Common.
In Hallowe'en Party, Ariadne Oliver is a guest at a friend's house in Woodleigh Common. She takes part in the preparations for the Halloween party at Rowena Drake's house where Joyce Reynolds is killed. Ariadne then asks Hercule Poirot to investigate, and Poirot travels to the English village to meet with several witnesses and find the truth.