Countless films, plays and TV comedies have mined the desperate humor in office life.

At first glance, The Receptionist, at Theater LaB, seems one more ironic riff on the mind-numbing banalities and soul-draining trivialities of Cubicle Land.

Then, midway through Adam Bock’s 2007 off-Broadway play, the playwright reveals that he is after something darker and more substantial. Just how well he succeeds is the question, and one likely to prompt a wide range of responses.

Beverly (Terri Branda Carter) serves the titular function at a firm of some presumed importance but unspecified purpose.

“Northeast Office” she blandly purrs as she answers the ceaseless flow of incoming calls, explains that boss Mr. Taylor (Bob Boudreaux) is out, and offers to put callers through to his voice mail as if that were the kindest act in the world. The business calls keep interrupting Beverly’s personal call to a friend and in-person gossip with co-worker Lorraine (Krysti Wilson). Beverly tries to guide each to more sensible love lives, as the phone chum has a thing for married men and Lorraine can’t get over her narcissistic ex.

Dapper Martin Dart (Alan Heckner) arrives “from the Central Office” and, while waiting for the absent Mr. Taylor, flirts with Lorraine as Beverly runs interference.

Mr. Taylor at last arrives and drops a troubling line that suggests the nature of the company’s business, changing the play’s mood from innocuous to ominous. It only grows more so as the purpose of Mr. Dart’s visit becomes clear.

Bock won a 2006 Obie for The Thugs, about a group of temps who suspect foul play in their building but who go unheeded because of their status. Yes, Bock has served real-life time as a temp and a receptionist. Just how highly he’s regarded as a playwright is indicated by this: The Receptionist’s off-Broadway production was directed by Joe Mantello (Wicked, Take Me Out, Assassins , etc.), one of Broadway’s most successful and in-demand directors.

Bock’s writing is astute and subtly amusing, especially in capturing the petty rivalries and conversational rhythms of the office routine. Yet while the latter half’s shift to a more serious mode produces some effective moments, this part of the play never seems as fully realized as the comic first half.

Like the play itself, Carolyn Houston Boone’s direction is strongest at conveying the characters’ interplay — boosted by the quick pick-up of lines and sharp timing of conversations breaking off as phones ring.

Carter is smoothly efficient and knowing as the experience-seasoned Beverly, finding understated humor in such quirks as her obsessive control of the office’s supply of pens.

Wilson strikes a neat contrast as the impulsive young Lorraine, brash, bubbly and flighty in her moves and spontaneous chatter.

As the mysterious visitor from the Central Office, Heckner is cool and genial yet a little remote. He’s also able to summon the quite different qualities later required.

Boudreaux projects the right troubled and preoccupied air as Mr. Taylor. He brings quiet believability to an enigmatic monologue about fishing (and other things) that opens the play.

It may not make much sense at the time, but makes a good deal more in retrospect, after one has learned where the play was heading.

everett.evans@chron.com