The worlds of Charles Dickens and Sir Arthur Conan Doyle collide in “A Sherlock Carol.”

The characters we meet in novels not only live inside the pages of books, but populate our brains, too.

And in Mark Shanahan’s head, Sherlock Holmes and Ebenezer Scrooge bumped into each other one day. “As a writer, I’ve gone all over the country (directing) ‘A Christmas Carol,’ plus my own version of ‘A Christmas Carol,’” says the playwright/director/Broadway actor. “And I love to direct murder mysteries, so I‘ve done a lot of them, (including) a lot of Sherlock Holmes plays.”

So he wrote “A Sherlock Carol,” a perfect mash-up of the two.

The regional premiere runs Dec. 1-17 at Florida Repertory Theatre, with previews running through Nov. 30.

The show played to popular and critical acclaim in both New York and London, with Shanahan directing.

“I’ve always loved a good mystery, ever since I was a boy,” he says. (Shanahan recently wrote and directed the world adaptation of Agatha Christie’s “The Murder of Roger Ackroyd.”)

A grown-up Tiny Tim begs Sherlock Holmes to investigate the peculiar death of Ebenezer Scrooge. COURTESY PHOTO / JOE DAFELDECKER

“I thought: what would happen if I combined ‘A Christmas Carol’ with Sherlock Holmes? What if I created this fun mash-up? As I write, the 12-year-old boy in me gets to be in the room with all these wonderful characters in the flesh. It feels great!”

A different twist

The idea of putting the logical detective in a situation where he has to deal with spirits, despite the fact he doesn’t believe in them, appealed to Shanahan.

“The plot is that one dark and stormy Christmas Eve, a grown-up Tiny Tim comes to Sherlock Holmes to solve the mystery of the death of Ebenezer Scrooge,” he says. “And it’s important to note Sherlock Holmes has lost his own way. This is a chance to figure out what could make a man change. Along his investigation he meets characters from Sherlock Holmes tales as well as from the beloved ‘Christmas Carol.’ It’s a wonderful combination of Dickens and Doyle.”

It’s a cast of six, with four playing multiple roles, he says, including spirits of the past, present and future who “guide us along the way and tell us the tale of Holmes. Eventually Holmes comes into contact with the spirit of Scrooge himself, who helps him figure out the mystery.”

Catch “A Sherlock Carol” Dec. 1-17 at the historic Arcade Theatre in downtown Fort Myers.

Included in the plot is a missing diamond, a missing will, an old love of Holmes and several descendants of the Fezziwigs.

And though the two classic writers never met in real life, “The ways in which these two stories by Dickens and Doyle intersect will surprise audiences,” Shanahan says.

“That’s one of the great points of putting these characters together. Holmes is such a logical character and fact-based. In ‘The Story of the Sussex Vampire,’ he says no ghosts need apply to his detective agency. It’s great fun to put him in contact with the story which is one of the greatest ghost stories ever told.

“In a weird way, it doesn’t matter if he winds up believing in ghosts or not. He will open his heart and learn the lesson that Scrooge learned, that we’re all here to help each other and live up to our potential, which is at the core of Dickens’s story.”

A Sherlock Carol

The play, he says, is a celebration of theater as much as it is a celebration of Holmes and “A Christmas Carol.”

“It’s highly theatrical and very sweet-natured, very family-friendly,” he says.

The play was slated for Broadway but was cancelled due to the pandemic; it opened Off-Broadway in 2021.

The play was staged yet again last year.

Named a New York Times Critic’s Pick, the paper called it a “clever, crowd-pleasing holiday comedy,” saying it appeals to both children and adults. It was also named Best Play by the Off-Broadway Alliance in 2022.

It makes sense Florida Rep’s presenting the regional premiere of “A Sherlock Carol.” After all, the play was chosen for its 2020 PlayLab festival and given a reading. And Shanahan’s previous work, including “The Dingdong,” (an adaptation of a French sex farce,) and “A Merry Little Christmas Carol” graced Fla Rep’s stage in 2016 and 2018, respectively.

Shanahan has also directed a number of shows for the venue, such as “Around the World in 80 Days” and “The Hound of the Baskervilles.” He himself was an actor in “The 39 Steps” on Broadway, so he knows how to draw that unexpected humor out of others.

Sherlock and Sherlock and Sherlock…

The list of stage and screen Sherlocks is a long one, from Basil Rathbone to Benedict Cumberbatch. Other famous actors have also portrayed him, including Boris Karloff, John Barrymore and Charlton Heston.

Every actor and writer put his mark on the famous detective, and Shanahan is happy to join that canon.

“There are lots of different Sherlock Holmes plays and murder mysteries,” he says. “I thought it’d be great fun to put these stories together. Audiences go to Christmas Carols around the country; it’s a tradition. Very often it’s a gateway for a younger person to see a live performance in a theater. ‘A Christmas Carol’ is incredibly valuable that way. And murder mysteries do something similar, they have their own audience.

“It’s great when audiences come to realize how much they love theater and will come back to see more. I wanted to combine those audiences with characters people know, but also reinvestigate them. People think they know what a Sherlock Holmes play could be like. This play asks you think of the character in new ways you may not have thought of them before. Tiny Tim grows up. Scrooge lives a long life and became the most beloved man. He gave generously, lived wisely. It’s a funny thing to think that the word ‘Scrooge’ means a miser — because Scrooge is a wonderful person who changed his ways. He’s a great hero.”

Shanahan is also an admirer of the famous detective. “Sherlock is a genius,” he says. “He can see clues that others cannot. That’s his great gift.”

But Sherlock Holmes also possesses a gift for writers.

“He’s malleable,” Shanahan says of the character. “He can be a smiley hero in some versions, an action star with Robert Downey Jr., a modern sleuth in the Benedict Cumberbatch versions. He can be a spoof or a silly character in the comedic versions with Michael Caine in ‘Without a Clue’ or with Will Farrell. He can be a very dark character.”

Shanahan’s happy that after presenting a reading of “A Sherlock Carol” a few years ago, Florida Rep is now giving it a full production.

“You have to experience it with other people,” he says. “Actors do incredible things before your eyes and transform the space and tell a story that thrills you. I love the theatricality of what actors bring to the table and the magic of their skill. They’re creating an entire world.” ¦

In the KNOW

A Sherlock Carol

· When: Dec. 1-17 (previews through Nov. 30)

· Where: Historic Arcade Theatre, 2268 Bay Street, downtown Fort Myers

· Cost: $65

· Information: 239-332-4488 or www.flordarep.org