Theatre, like religion, is heavily reliant on faith: You're often required to trust that a higher power (whether God or a playwright) will lead you through difficult times to a better place, and important tests may take on curious, unfamiliar forms. Keith Bunin's The Busy World is Hushed, now at Playwrights Horizons, is both an obvious and a deceptive test.

After slogging through stilted dialogue, only intermittently effective performances, and a perilously predictable plot, you might think that nothing can come of this exploration of hope in a world that thrives on instant knowledge and even quicker gratification. But if on the surface Bunin is treading well-worn dramatic byways, it soon becomes clear that he has more on his mind: This is a richly spiritual work that transcends the surface-level examination of devotion it initially seems to be and instead asks real questions about the place of religion in today's, well, busy world.

But you must first work past the tropes that try to mire the play in the turgid world of the typical. Specifically, the believer (Jill Clayburgh), here Hannah, an Episcopal priest; the nonbeliever (Luke MacFarlane), her son Thomas, an itinerant wanderer and/or runaway; and the man in the middle (Hamish Linklater), Brandt, the struggling writer Hannah engages to help her write a book and who soon becomes tangled up with the wanderlusty Thomas.

He might be forever trying to find himself by playing a game he calls "Get Lost," in which he does just that for days, weeks, or months at a time, but he's also intent on puzzling out the truth of the life and death of his father, who drowned before he was born. Brandt's father has just been diagnosed with a brain tumor of indeterminate seriousness. And Hannah wants only to hold onto Thomas for as long as possible.

The uncertainty flooding each corner of this razor-edged triangle is reflected in the source for Hannah's book, a mysterious Coptic Gospel that might predate the works of Matthew, Mark, Luke, and John and provide enlightenment about the "true" Jesus Christ. (Though it's not intended to be the hotly disputed Gospel of Thomas, there are a number of similarities.) In other words: How do you proceed when no one knows anything about anything?

The deeper Bunin digs, the livelier his play becomes. Story specifics matter much less than the characters' internal journeys toward a greater understanding of what they most need to find, and Bunin's ruthless consistency in presenting them lends compelling, unyielding authority to their quests. If nothing he's written is likely to change any minds, this remains an uncommonly even-handed look at the issues and disagreements that can divide families, friends, and countries (and have for nearly 2,000 years).

Mark Brokaw directs with a light touch, nimbly but carefully charting the Wall Street-tumultuous tension everyone must paddle through. He's less successful at massaging the performances so that everyone onstage registers as a conflicted, contemporary person and not a hyper-literate, overly loquacious forensics major. As Bunin's dialogue often rings with antirealistic tones suggesting Richard Greenberg was a major influence, it's crucial that the director and actors work especially hard on maintaining believability throughout.

That doesn't happen here. Linklater too often defaults to a stereotypically stiff-lanky gay man for Brandt, while MacFarlane's Thomas is almost satirically free-spirited and energetic. If they occupy unbelievably opposite poles generally, they both come together in their inability to translate most of their lines into everyday-sounding speech. That they have no apparent romantic chemistry together proves strangely incidental, though some might emerge if we could ever believe what they say.

That's less of a problem with Clayburgh. If she still trips over a few clunkily constructed lines, her portrayal is a fascinating study in how to overcome such difficulties. Initially overplaying Hannah's staunch patrician nature, she ensures that her liberal (and often borderline incredible) interpretations of scripture and her eventual role in the Thomas-Brandt pairing have a greater impact. And while her performance has no shortage of feeling, her heart is strictly hard-edged, summoning exactly the blocked emotions and need for spiritual anchoring that has driven Hannah the entirety of her adult life.

If Clayburgh's character is the only fully rounded one, she's not operating in a vacuum. Linklater's and MacFarlane's personalities make for colorful contrast onstage, and Allen Moyer's set - a striking mixture of secular and religious influences (stacks of shelfless books beside stained-glass windows) - gives the play a real visual authenticity that's matched by Bunin's knowing and caring, if seldom witty, writing.

Little, however, says more than the title, taken from an Episcopal prayer that God provide support until both the end of the day and the end of days, and the wisdom to know the difference between the two. Bunin's characters are forever struggling to discern the truth of that benediction; prospective audience members can be assured that if they will be tried along the way, their faith in Bunin will not ultimately be misplaced.

The Busy World is Hushed
Through July 9
Playwrights Horizons Mainstage, 416 West 42nd Street between 9th & 10th Avenues
Tickets online and current Performance Schedule: TicketCentral