Everybody loves a good whodunnit movie. Based on Agatha Christie’s 1969 novel Hallowe’en Party, A Haunting In Venice slow burns the story of a murder during a séance at a Venetian palazzo and stars Jamie Dornan, Michelle Yeoh, and Tina Fey. Kenneth Branagh plays Hercule Poirot, and also directs. Screenwriter Michael Green (Logan, Blade Runner 2049) spoke with Creative Screenwriting Magazine about his writing process in his third adaptation of a Christie novel.

Green is acutely aware of the intense passion of Agatha Christie fans, so he knows his film adaptation require their seal of approval. The screenwriter has previously adapted Death On The Nile and Murder On The Orient Express (both directed by Kenneth Branagh), so he is no stranger to the whodunnit genre or the author’s work.

“The idea to adapt Hallowe’en Party occurred to me while we were on the set filming Death On the Nile. A set of dominoes went off of my mind about what might be an interesting third Christie movie; an elevated horror within the mystery genre for more grown-up audiences,” says Green. “I just said, ‘What do you think about doing something in this tone in space and where we take a few liberties with the story?” The producers promptly contacted the Christie estate regarding Hallowe’en Party, who immediately expressed their enthusiasm and support.

Michael Green considered how they were going to adapt the beloved mystery novel into A Haunting In Venice. They decided to compress the events over a single Halloween night and set in a palazzo In Venice.

Michael Green

“I could see his [Kenneth Branagh’s] eyes light up because he’d had some personal experiences spending a lot of time in Venice. He talked about being there on a certain night with the masks, and the mist coming over the river, so he was really able to start to see the images of masked clad figures coming through the canals, the boats being pulled through the mist as the rain starts to fall… and sure enough those images are in the film.” Branagh’s emotional connection to Venice set the tone and mood of A Haunting In Venice.

Green On Agatha Christie’s Writing Process

Michael Green confesses that he wasn’t the biggest Agatha Christie fan. “I read some books, but I found a love for them on the job. Now, I read her mostly for pleasure. ”

The screenwriter read her autobiography and her notebooks, so he has a strong grasp of her literary intention and style. “There’s so many things to admire about her level dedication her craft or just the writer instinct to get up and work all the time. She really pushed herself until her later years.” After adapting three Agatha Christie novels into films, Green has drifted into fanhood. “The more I’ve learned about her, the more I’m impressed with the craft she brought to writing. She would constantly challenge herself to reinvent what writing was to her.”

On occasion, Christie would publish under a pen name so she could write personal stories that weren’t what her audience expected. She even wrote plays and short stories at one point. “She could dip in and out of elevated prose at will. And that’s a thing to admire. She could keep it simple, she could go plot-focused, and just do something for the sheer joy of it. At other times, she would steep in the language when she felt like it and was a word stylist.”

I can’t say how Christie built her clocks, but she cared  about clocks and building them right.

Agatha Christie was also a big reader. “She and her second husband would read Shakespeare to each other. There was a real love of word and of classics.”

Who Is Hercule Poirot?

Hercule is retired and living in self-imposed exile in Venice, when he’s thrust back into his former profession to solve a murder at the palazzo. He’s extremely observant, but he also has a detachment to him.

“Part of the fun of adapting these books is that Hercule Poirot has been read and imagined by readers since he came onto the scene in the 1920 in The Mysterious Affair at Styles. Our interest was to make sure that we added something to that and our version was unique.”

“Poirot might be fussy and have his preferences, but he has his gift, he has his particular genius, and that genius comes at a cost. That’s the ability to see the worst in people and to see the world as it really is – where it’s broken and bent and immorality reigns, so that he’s able to find some justice for those who’ve lost or those who have been hurt.”

Hercule Poirot can be gruff and overly-methodical. “That’s his brain trying to find order where he can because there’s so much disorder in criminality,” adds Green.

Hercule Poirot (Kenneth Branagh) Photo courtesy 20th Century Pictures

The Adaptation Process

Adapting a novel into a screenplay requires many creative decisions to transfer the story into another medium. “There were no ‘musts’ that were determined by anything other than my instinct as I was poking around. I really appreciated the springboard premise of a murder at a Halloween party. And then, that was the springboard into having to face the possibility of what isn’t and what might be.”

Michael Green also knows the temperament of the studio, what they need, and what to expect.

Part of the adaptation process included “how much plot detail a filmed version of an Agatha Christie book can sustain.” The screenwriter also fine-tuned his knowledge how mysteries work.

“An Agatha Christie book might have something like 20, 400, maybe 2,000 data points that tell the story, and a movie can sustain maybe 100 or 150.”

Michael Green also studied the edits of his previous Christie adaptations.  That made him realize which plot points weren’t essential to the story. “In the natural selection of what’s being done, was motivation. To who? Why they might have done something? Who they are?  What are they hiding? And what are they hiding under that? What makes them be in that sealed room to have a stake in the story?”

Constantly revisiting these questions allow Green “to refine my own approach into what our takes on these films seem to be more interested in. I knew that I could describe the target better.” These answers helped him decide which clues and plot points audiences might be most receptive to. Kenneth Branagh, the cast, and various dramaturgs assisted in this process.

After Green completes a draft, he seeks input. “We go through the script a number of times with Kenneth. From first read to production concerns, to a read with his thoughts as an actor for his own role.”

The studio was heavily involved in the development process from an early stage. Their notes were additive from outline to script stage. It was helpful for Green to get advice when he came to a decision tree branch where the story could progress along one of several paths.

“And lastly, the actors provided input. One fun thing about this is I think when the actors get the script, they are pretty close to done. We’ll do some stuff for the actors to shape it. It’s like you’re making the suit custom fit.”

Keeping The Mystery Alive

Whodunnits revolve around a crime – typically a murder, there’s a detective and a group of suspects all of which have a similar degree of motivation to commit the crime. These stories thrive on changing character focus and points of view, directing and misdirecting, pivoting, and confusing, so the audience is a sleuth in real time until the end.

This is where plot-heavy genres such as this one must carefully balance plot progression with character development. “It’s about making sure you care about them and your characters feel well-rounded and more modern,” says Green.

A key writing insight Michael Green had during Death On The Nile was to make sure all the suspects personally knew the victim to keep them sufficiently motivated and invested. A stranger killing a victim wouldn’t be as interesting to the story.

Every mystery needs a conclusion; the unveiling of the killer. It needs to be organic and logical as all the seemingly minor clues are collated and processed into a verdict by the detective.

“I’m someone who doesn’t overvalue surprise,” shocks Green. “You have to give the audience enough along the way so that they could have picked up on it. You have to make your math check out. You have to make sure that everything was built in and you’re not cheating by throwing in some last minute twists. And it has to make emotional sense. Why they did it, and that there are reveals in that moment that answer some questions.”

“And then, lastly, how do you write these scenes and not have them go on forever? How do you do it in a reasonable number of pages? I know that those scenes specifically are going to be six to eight pages.”

Final Thoughts

Michael Green doesn’t dwell on his scripts after they’ve been filmed. He enjoys a final goodbye. “I’m worried about looking back. I’m thinking about the next one. I’m worried about finding new facets of my voice and reinventing my own process so that every feature I write seems new. I sit in a different chair with each new script. How can I make this a new puzzle for me to figure out?”

“I need a new challenge and puzzle for my brain to just keep it engaged. Because the minute my brain feels like I’ve done this before, I can feel a softness come in, or it feels like that puzzle’s already been solved.”

The screenwriter doesn’t admonish writers who stick to a particular genre. “Some of my favorite writers and friends and whose work I completely admire are the best in the world at what they do and they have a genre. They have a thing or a few things that they do well so they stick to it.“