Sleuth, solve thyself.

In“Mrs. Christie,”it doesn’t matter if you envisage and construct mysteries that entrance readers worldwide, or if you’ve got the smarts to crack a riddle that’s stumped throngs of fans and academics. For you, too, the self is a fathomless abyss, one that’s liable to surge into a tidal wave and smack you upside the head.

In Heidi Armbruster’s champagne flute of a play, which had itsTheatreWorks Silicon Valley西海岸premiere Saturday, Oct. 7, at Mountain View Center for the Performing Arts, Agatha Christie (Jennifer Le Blanc) can’t see what’s plain to everyone else: Her marriage to Archie (Aldo Billingslea) is over.

A century later, raging Christie fan Lucy (Nicole Javier) is a human dumpster fire. She pilfers whichever treasures and downs whichever beverages happen to lie onstage in any given scene, fulminates in ageist remarks against her new friend and fellow fan Jane (Lucinda Hitchcock Cone) and chafes against everyone she meets — all because she can’t acknowledge the blustery grief at her core.

As Armbruster weaves together the women’s twin tales of groping in the dark and learning to see themselves, she unspools another mystery: what happened to Agatha Christie when she disappeared for 11 days in 1926, prompting a nationwide search.

The real-life Christie never explained what drove her, and in building toward a theory of her own, Armbruster sprinkles in morsels of clues to whet your inner Hercule Poirot. Christopher Fitzer’s whirligig of a set design, a richly paneled, bookshelf-lined drawing room, physically manifests the script’s puzzle-like construction. The way every piece pops, swivels or morphs, by the end of the show, you half-expect a portal to Narnia to open.

At her best, Armbruster, who’s an actor in addition to a playwright, peels right to the pith. In much of the play, to speak isn’t to hold forth or drop witticisms but to vie for an aim, to wrench the proceedings in a fresh direction. The result, under the direction of Giovanna Sardelli, fizzes and dizzies.

When Le Blanc’s Agatha and Billingslea’s Archie have it out, every little wound and exposure is a new window into the embarrassing, human core of who someone is. When Javier’s Lucy tries to flirt or force a secret Christie notebook from the hands of a scholar, William (Max Tachis), the two volley, bluff and backpedal their way into a pas de deux. In the end, the only way Lucy can escape is to melt out of William’s arms.

This cast blazes with talent and craft. Javier keeps devising new ways to make Lucy detonate, often multiple times within a line. She’s a 180-puller, an impulse machine, a swirl of heavings, huffs and itches, and Javier makes it all make sense, like a volcanic chemical reaction that’s only playing out according to natural laws.

As Hercule Poirot come to life to spar with his creator, William Thomas Hodgson whips up a Belgian accent as pungent as overripe cheese. As both William and Christie’s publisher, Collins, Tachis is elastic of face and form, giving the impression that he could bend like a Looney Tune and throw in a few circus tricks on the way.

If successful mysteries know exactly how much information to supply, and when, “Mrs. Christie” ultimately overexplains itself, insisting that Agatha and Lucy not just make discoveries but tie up narrative bow upon bow on top of them. Still, the show offers wise counsel to those in the lonely throes of mourning: A true artist or true fan is never really alone. A sparkling creation is no human companion, but it’s deep, fruitful and constant all the same.

Reach Lily Janiak:ljaniak@sfchronicle.com