Six characters sitting in a straight line across the stage, listening to voice-over of an unseen, heavily sedated guru woozily giving life instructions: That’s the basic setup of Bess Wohl’s “Small Mouth Sounds.” Watching the characters as they wait for enlightenment sometimes prompts this thought toward the playwright: Do something.

Wohl actually is doing lots, even if the dialogue is minimal in this 2015 off-Broadway hit, now getting a nearly silent movie treatment at Bethesda’s Round House Theatre. The characters at this mindfulness retreat are instructed not to talk, which of course is an invitation to slapstick — especially since nudity is encouraged in this let-it-all-out milieu (and since there may be bears in the woods).

Mostly, though, Wohl’s unusual script is subtler, an exercise less in doing — the thing we usually want from drama — than in being. Breathe deep and listen to the crickets chirp as the actors bed down in random pairs, with one man switching off the portable lantern just as his bunkmate starts to read, and with another character settling in on a pillow but being yanked awake by the crunch of a smuggled potato chip. The attentiveness gets that fine: It’s as delicate as a crisp.

The play’s thin-as-mist plot is not absorbing for each of its 100 minutes, especially not with the guru (voiced by Timothy Douglas) coughing and droning into his microphone at his trapped pupils, sounding a little too much like the HAL 9000 in its waning moments. The supplicants gaze into the distance, and we gaze back. They think, Om. We think, Um . . .

Yet director Ryan Rilette and his team clearly relish filling in the blanks, aided by backstories Wohl wrote for each character but that we never get to hear. Instead, we see little hopes and fears as they tellingly react to words like “pain” and console each other with a wordlessly passed packet of tissues. Beth Hylton is both vulnerable and a little ditsy as one half of a lesbian couple experiencing some kind of grief; as her wounded, lonely partner, Andrea Harris Smith gets some of the funniest and most touching moments in the show.

A vaguely famous, enviably flexible and undeniably handsome man is played with bristling confidence and a catlike smile by Maboud Ebrahimzadeh. James Whalen is compliant yet bedeviled as the one member of the group plagued by mosquitoes; Michael Glenn bumbles deftly as the sort of sad sack who can’t even get a pen to work (the one role Wohl piles too high); and Katie deBuys seems at risk of a crackup as an addled woman who enters late dragging a jumbo suitcase packed as if for a world cruise. Give this batch of actors credit for being persuasively alive and revealingly interconnected at all times, even when there’s nothing for them to do but wait for the next thing to happen.

Debra Booth’s wood-toned set efficiently blends indoors and outdoors as the characters struggle to match action to intention. Wohl wants the story to be slow, and it can be too slow — the intermission-free evening is not always in perfect harmonic balance. But the cast is.

Small Mouth Sounds, by Bess Wohl. Directed by Ryan Rilette. Lights, York Kennedy; costumes, Debra Kim Sevigny; sound design, Roc Lee; projections, Alexandra Kelly Colburn. About 100 minutes. $50-$67. Through Sept. 23 at Round House Theatre, 4545 East-West Hwy., Bethesda. 240-644-1100 or