The Pennsylvania Playhouse is providing a welcome respite from musicals and comedies by staging a whodunit based on Dame Agatha Christie’s novel, “And Then There Were None,” the world’s best-selling murder mystery novel of all time.

“And Then There Were None” continues through Oct. 13 at Pennsylvania Playhouse, Bethlehem. The opening night, Sept. 27, performance, was seen for this review.

The play’s story is set on an island off the English coast. Eight unsuspecting guests arrive at an isolated mansion with their suitcases. They are expecting to have a good time. They’re met by the butler and his wife, who announce that the host, whom no one has ever met, has not yet arrived.

Shortly after the guests settle in, a disembodied voice, later located on a phonograph record, accuses all 10 of having committed murder. When some of the alleged murders are murdered themselves, the plot thickens.

The book was published in the United States in 1940 as “And Then There Were None,” taken from the last words of the song and nursery rhyme.

In the Playhouse production, the framed lyrics of the song are hung on a wall near the dining room table on which 10 white soldier figurines are grouped. As the play progresses through its three acts, the soldiers disappear one by one.

The production, capably directed by Marian Barshinger, features a varied cast of 10 actors who have a way of disappearing themselves. Before doing so, each has at least one opportunity to be in the limelight.

Jillian McLuhan makes the most of her many “spotlight” moments as the secretary Vera, whose fear and vulnerability is entirely believable.

John Corl is right at home on stage as Sir Lawrence Wargrave. Interestingly, the book and play has no detective to connect the dots and bring everything to a conclusion. Instead, Wargrave tries to do it. Corl is convincing up to the task.

Ryan MacNamara as Capt. Phillip Lombard handles well the differing aspects of his character. Marcy Repp also has some charming moments as Mrs. Rogers, switching effortlessly from complainer to attentive servant.

Others in the cast are Gary Boyer (Rogers), Brian Wendt (Fred), Drake Nester (Anthony), Shaun Hayes (Blore), Dale Beltzner (the General), Jenelle Castrignano (Emily) and Ross Morris (Dr. Armstrong).

The acting and directing challenges, presented especially in the first act, are to avoid inertia in blocking, keep the energy going by picking up lines faster and keeping vitality in the line delivery, even when the volume is meant to be soft. Sometimes in the Playhouse production that doesn’t happen. It’s mentionable, and very fixable.

Christie, who described the mystery as her most difficult to write, adapted it herself for the stage in 1943. She and her producers changed the book ending to something they thought would be more palatable for theatergoers.

The local production contains a puzzle of its own: What ending are Pennsylvania Playhouse audiences going to see?

This reviewer is not about to give away any clues. After all, it’s a mystery, so you are going to have to go see the play and find out for yourself. As one of Christie’s most famous detectives would say, “Use your little grey cells.”

Tickets: Pennsylvania Playhouse Box Office, 390 Illick’s Mill Road, Bethlehem; paplayhouse.org; 610-865-1192