How to solve an onstage mystery like the one in 'Holmes and Watson'

Watch the eyes. Don't forget the evil genius. Keep an open mind.

Those are basic tips for audience members hoping to solve the mystery along with — or before — characters in Park Square Theatre's "Holmes and Watson," which opens Friday. The latest Park Square summer thriller by Jeffrey Hatcher ("Sherlock Holmes and the Suicide Club," "Sherlock Holmes and the Ice Palace Murders"), "Holmes" opens with sidekick Dr. Watson receiving word that the presumed-dead sleuth is alive and that three people are claiming to be him.

Who's the "real" Holmes? And can Watson (Bruce Roach) figure it out before the audience does?

If a theatergoer — or anyone — wants to solve a mystery, retired Burnsville police officer Wally Lind says the eyes have it.

"People who are lying usually don't look the interrogator in the eye. They look to the side or down," said Lind, who also logged time as a crime scene investigator. "That's what would make me immediately suspicious: If they don't look me in the eye or they don't shake my hand or stand next to me. They physically back away."

Wayzata-based Hatcher, who has written devious plots for movies (Helen Mirren in "The Good Liar" and Ian McKellen as the titular "Mr. Holmes") as well as in the virtual realm ("Riddle Puzzle Plot"), offers a few tips, starting with assuring audiences that the drama will play fair.

"You're giving them all the information they would need to know and the solution isn't based on some piece of information they wouldn't have," said Hatcher, whose preferred method of fooling theatergoers is to mess with what they know — or think they know — about mystery tropes.

Citing classics by Agatha Christie and a woman in "Sweeney Todd" whose presence is mysterious until you realize she's a crucial character who has been lurking in plain sight, Hatcher stays clued in to audience expectations. Then, he upends them.

"I'll use the 'Die Hard' example. The Alan Rickman character, Hans Gruber, says the bad guys are there because of politics. No, they're not. They're there to steal money. It's a magician's trick: 'Don't look here. Look there,'" said Hatcher. "You point at one thing when really they should be looking at something else. Without giving anything away, that is definitely happening in 'Holmes and Watson.'"

The title characters' relationship is what it's all about for Tom Gottwalt, who knows his Holmes. He's president of the Norwegian Explorers, a local society that takes its name from a theory about what Mr. Elementary-My-Dear-Watson was doing when he disappeared from Arthur Conan Doyle's stories. Members meet monthly to discuss Holmes tales and ephemera.

"The mysteries are almost secondary to the relationship between Holmes and Watson and the atmosphere of Victorian London," said Gottwalt, whose group will attend Park Square's play. One of the largest Holmes societies in the world, members are also anticipating this fall's Minnesota History Center exhibit, drawing on the world's largest collection of Sherlockiana, which happens to be housed at the University of Minnesota.

Audiences may be able to sniff out the real Holmes by studying how the pretenders — played by Paul de Cordova, Peter Simmons and Pearce Bunting — interact with their supposed best friend, Watson. While Gottwalt hasn't seen the play, he suspects it's in the quieter moments when the relationship will emerge.

"In most of the stories, there is something we call a 'cozy' and if Hatcher is doing his job, there will be one. It might be something like Holmes and Watson, sitting in their rooms at Baker Street, with Holmes doing an experiment and Watson reading a paper. But it's really a chance for Holmes to demonstrate his deductive prowess," Gottwalt said.

Another place to look is the suspects, of course.

"They are often inconsistent in what they say. It's harder to remember a lie. It's easier to remember the truth. Or a tremble in their voice," said Lind. "Look for someone who gives one answer and then gives a different answer in another situation. Or they come up with additional details, trying to steer the investigation away from them."

Whether or not Professor Moriarty is listed in the program, Gottwalt thinks audiences should be on the lookout for Holmes' crafty nemesis.

"He's often not seen but he lurks behind all evil. Often, if we are at a conference and the battery in a microphone goes dead or something goes wrong, we'll say, 'Moriarty must have done it,'" said Gottwalt, noting that Hatcher is a Norwegian Explorer. "I'm guessing he'll weave something into the play. One of the three [would-be Sherlocks] might be a plant or something."

Recalling surprises that delighted him, such as in "The Sixth Sense" and "The Crying Game," Hatcher loves hearing someone in the audience deduce the solution just before the detective does. For the playwright, hearing a satisfied "I knew it" in the audience means he has done his job. Ideally, he hopes audiences come in as "blank slates."

"If they want to try to outguess it, I don't want to blow the surprises but I will say that there's usually a baseline in any play or drama that says, 'You must believe this in order for everything else to work,'" said Hatcher. "I do think that 'Holmes and Watson' has one or two tricks up its sleeve, based on that baseline being wrong."

In other words, potential audiences: Prepare to think you know what's going on in the mystery. And prepare to be wrong about all of it.

'Holmes and Watson'

Who: By Jeffrey Hatcher. Directed by Michael Evan Haney.

When: 7:30 p.m. Tue.-Sat., 2 p.m. Sun. Ends Aug. 21.

Where: Park Square Theatre, 20 W. 7th Place, St. Paul.

Protocol: Masks required.

Tickets: $27-$55, 651-291-7005 or parksquaretheatre.org.