They could all use some therapy.

That's not the first or even the fifth thing that usually comes to mind when one thinks of an Agatha Christie mystery, least of all "The Mousetrap," her witty whodunit that opened Thursday in the Guthrie Theater's first-ever production of the show.

But as the snowed-in characters in Monkswell Manor start to squirm under the pressure of a murder investigation, we get to see all the frightened children clamoring for air behind their adult masks.

Hyperactive architect Christopher Wren, aloof world traveler Miss Casewell, even manor owners Mollie and Giles Ralston bear scars and secrets that leach into their souls. And in a crisis, they instinctually seek to recapture lost innocence or right the wrongs of the past.

The psychological mess that surfaces in "Mousetrap" and makes you want to give these characters a teddy bear or a hug takes none of the entertainment value away from Tracy Brigden's deft staging.

Working with a strong design team on Walt Spangler's stately, elk-adorned set, Brigden has found ways to deepen the story and have fun.

When the guests, err, suspects, arrive and say their names, each is temporarily bathed in a noirish spotlight and accompanied by a musical flourish. That's true for Wren (Greg Cuellar, going to the top but not quite over), Casewell (Emjoy Gavino, mysterious and fashionable), Major Metcalf (Pearce Bunting in his big-bellied, manspreading Guthrie debut) and Mr. Paravicini (Matthew Saldívar, aka onetime Scrooge, in a killer turn as the deadpan charmer).

But it's not as clearly drawn for Detective Sgt. Trotter (Matthew Amendt), and that's because of when and how he arrives.

Brigden elicits really fabulous performances from her cast. Amendt and Saldívar are especially noteworthy for not just playing along with the narrative whose ending they know, but for playing it out in a way that shows us that they are discovering the facts at the same time we do.

The Ralstons are played with tension and mystery by Peter Christian Hansen and Monette Magrath. The have so-so chemistry, but Hansen is a surefire performer and the pair pull it off.

The cast also includes Mo Perry as the miserable mutterer Mrs. Boyle, a wretch whose role in the plot is to elicit a bunch of screams. Perry plays it like a natural, helping this "Mousetrap" to spring with entertaining suspense.

'The Mousetrap'

Where: Guthrie Theater, 818 S. 2nd St., Mpls.

When: 7:30 p.m. Tue.-Fri., 1 & 7:30 p.m. Sat., 1 & 7 p.m. Sun. Ends May 18.

Tickets: $32-$92, 612-377-2224, guthrietheater.org.