Watchful eyes should pay attention for more than just whodunit in “The 39 Steps” at Whidbey Island Center for the Arts.

The classic murder mystery by filmmaker and master of suspense Alfred Hitchcock gets turned on its head with a humorous treatment by playwright Patrick Barlow, adapted for Whidbey Island Center for the Arts (WICA) by director Deana Duncan. “The 39 Steps” is about a man pursued for a crime he didn’t commit by police and by a spy ring for information he doesn’t have, fleeing across Scotland with a beautiful woman and the country’s security depending on him.

It’s serious, humorous and plenty self-referential. References to other famous Hitchcock stories such as “Rear Window,” “The Birds,” and “North by Northwest” are peppered throughout the show in a knowing wink. But the story doesn’t stray more than a turn or two from the path laid by Hitchcock in his original thriller.

“It’s basically the movie,” said Duncan, who is also the programming and production director at the Langley-based arts center. “But Alfred Hitchcock did a serious movie and Patrick Barlow did a spoof.”

That means the plot tracks the same arc. The difference is in the delivery, and that’s up to the production and actors to pull off convincingly.

“You’d be a fool to mess with it,” Duncan said.

Viewers to the show, which takes the Langley stage this weekend and next weekend, can expect laughs, gasps and a dash of thrill.

How would Hitchcock himself review the changes?

“I think he’d love it,” said Phil Jordan, an actor and director tasked with soundboard operation for “The 39 Steps. “He was into camp.”

The story includes espionage, counterintelligence, murder and romance. All of the depths of the tale, truly made into what Duncan called a respectful, loving farce by Barlow, are told by a cast of only four actors — Tristan A.B. Steel, Bristol Branson, Kent Junge and Katie Woodzick — and eight stage crew. The actors will embody 70 characters, both animate and inanimate, as everything from a few different people in the tale to a plane or train.

“It’s intense,” said Jordan, who is responsible for 300-plus sound cues.

“The 39 Steps,” more than any other WICA production Duncan had worked with, is relying on technical timing. There are eight image and video projections, sound effects, ample fog and even part of the theater seating was converted into an extension of the stage to help cover the range of settings needed.

There’s a moving train scene in which the locomotive comes to a screeching halt, a plane crash and a car crash. It involves the actors, a projection and a precise sound cue to pull off the illusion and keep viewers engaged. None of the effects are as crucial for their dramatic effect as the gunshot, however, and Jordan. Too early or too late, and what should be a stunning moment turns into a laughable mishap.

“It’s great fun for an actor or a director to be up there and see it on stage,” Jordan said, adding that he has relished seeing the audience’s reactions to the stage theatrics and effects.

References to other famous works at least tangentially related are obvious in the course of the play, Duncan said. Viewers should keep an eye and an ear out for clues to “The Pink Panther,” James Bond, Monty Python and other works.

“It’s pretty in your face,” she said.

One of the only subtle references is one of the hallmarks of a Hitchcock film: an Alfred Hitchcock cameo. That one, a week into the three-weekend run, had not been discovered to Duncan’s knowledge by anyone other than Jordan.

“I’ll buy you a drink if you spot it,” she said.

The world of “39 Steps” begins in the lobby for the show. At the bar, a special play-themed cocktail was concocted by Cadée Distillery in Clinton called “The Smoking Gun.” Decorating the posts and windows are posters for Hitchcock’s other famous films: “Vertigo,” “Psycho,” “To Catch a Thief,” and others.