A playwright would seem to be courting disaster when he stocks Scene 1 with a bottle of -- symbolism alert! -- Dead Sea sand. And when the waifish woman cradling the bottle observes that it represents spiritual searching and "the sweat from the building of civilizations" -- you might be tempted to write the whole script off as a piece of ham-handed pseudoprofundity.

But there's more finesse to "You Are Here" than its portentous Dead Sea metaphor might suggest. Canadian playwright Daniel MacIvor has a flair for characterization and an ear for the comic idiosyncrasies of modern speech, and his ungainly novelistic canvas teems with chatty, wayward personalities. The play's mercurial protagonist is Alison, who owns the sand-filled bottle. MacIvor surrounds her with a spectrum of lovers and colleagues and quirky incidental characters, such as an expletive-prone gigolo and an arrogant publishing Brahmin (who, in one of MacIvor's devastating satirical touches, edits a rag called Charles: The Very Magazine).

The interactions of this motley crew can be poignant and hilarious when matched with the kind of knockout acting found in Theater Alliance's American premiere production. Setting the tone is Jennifer Mendenhall's virtuoso rendition of Alison, a vulnerable journalist whose moods can turn on a dime. From the moment she creeps onstage, barefoot and clutching the sand-filled bottle, Mendenhall lends the production a riveting energy. And that's no easy task, since the play's central conceit -- Alison remembering her life -- calls for numerous monologues to be self-consciously delivered directly to the audience. But Mendenhall manages to suffuse these speeches with humor and urgency, while making her character persuasively complex.

This is a woman who can be, by turns, tart, fragile, exuberant and fierce -- and she's not above hurling doughnuts when she is feeling petulant.

The eight other actors also turn in stemwinder performances, particularly Michael Russotto as Alison's amiable pal Richard. Even when his lines amount to the likes of "Whoa" and "Hey," Russotto exudes a goofy charm, bolstering the play's suggestion that Richard is the frog prince that Alison has tragically failed to kiss. Also terrific are Kathleen Coons as a plasticy starlet, dressed to kill in black fashion boots (costumes are by Catherine F. Norgren); Brian Hemmingsen as a brooding film director; and Annie Houston as the editor of Charles. Under Gregg Henry's direction, the movements of the performers about the stark stage -- drenched with John Burkland's melodramatic lighting and unfurnished except for a chair -- speak volumes about the power dynamics between the characters.

But MacIvor wants to do more with "You Are Here" than create juicy roles for actors: He also aims to take Alison, and the audience, on a philosophical journey, and on that level he is not as successful. Although the sprawl of the narrative emphasizes the play's overarching question -- How do we orient ourselves amid the glut of everyday experience? -- the focus can feel aimless. We get devastating lampoons of film shoots and publishing parties. There are conversations about beet juice and ice cubes and Hindu philosophy. And then, every so often, the characters pause to peer into the existential abyss -- Alison's reflections on the Dead Sea sand being a case in point.

It's colorful, daring stuff, and the performances are delectable, but one can't help feeling that, overall, "You Are Here" amounts to less than the sum of its parts.

You Are Here, by Daniel MacIvor. Directed by Gregg Henry; set design, Tony Cisek; costumes, Catherine F. Norgren, lighting, John Burkland; sound, Kevin Hill. With Tim Carlin, Daniel Ladmirault. Approximately 21/2 hours. Through Nov. 13 at the H Street Playhouse, 1365 H St. NE. Call 1-800-494-8497 or visit www.theateralliance.com.

Theater Alliance's Michael Russotto and Jennifer Mendenhall help keep Daniel MacIvor's play humming even when it overreaches.