Three hours fifteen minutes of people doing not a great deal more than sweeping up litter in a cinema after screenings, turns out to be seriously absorbing stuff. Little happens over long periods in Annie Baker's Pulitzer-winning play which arrives here from New York with some of the original cast.

It begins with Sam (Matthew Maher) showing newbie worker Avery (Jaygann Ayeh) the ropes. You sweep like this, pick up litter like that. Spilt soft drinks are mopped up after the last show. It's a simple job.

Sam Gold's production makes a virtue out of hardly anything. Little activity is accompanied by dialogue which is as notable for its long silences between sentences as the sentences themselves. Plot development takes second place to character building. Take, for instance, the game that Avery and Sam like to play. Sam gives two random names of actors from American cinema to Avery, to which Avery responds by linking them with his encyclopedic knowledge of the subject. Both are introverted geeks and each hankers after the job of projectionist currently held by Rose (Louisa Krause) who Sam thinks only got the job because the cinema's owner "thinks she's hot."

We watch the action, if you can call it that, from the screen's point of view. David Zinn's realistic set of a neglected auditorium is crowned with stained ceiling tiles. Judging by the brown décor and the rows of worn flip-up seating, it was built in the 1970s and hasn't seen a refit since. This soundproofed, hermetically-sealed room in which nothing changes is the inert dramatic opposite of the heart-quickening stories people pay tickets to watch in cinemas. Though, of course, not the people paying for tickets for this theatre.

Still, change, it turns out is in the offing. Much to the regret of Avery, Rose's 35mm projector is going to be replaced with a digital machine by the cinema's new owner. Watching a film will no longer entail, well, watching film. Rather, as is happening to cinemas all over the world, the infinitely variable magic of the negative is being replaced by pixels, each one a clone of itself. So in many ways Baker's play is a lament for a cinematic era that is being extinguished by a largely unopposed revolution.

But it's also a play that captures the ebbs, flows and sudden eddies of unremarkable lives. Yet, as with all lives there are moments of drama here, even for Avery, Sam and Rose with whom Sam, it emerges, is in love. A sub-plot involving small-scale fraud builds into a racially loaded dilemma for the African American Avery who is the least guilty of the crime and the one who falls under most suspicion.

In theatrical terms, Gold's production is the opposite of the thrillingly flashy style of direction developed by Britain's golden boys of theatre, Rupert Goold and Jamie Lloyd, whose fizzing productions, as brilliant as they often are, feel driven by a fear that their audience might just experience the tiniest whiff of boredom for a passing nano-second. Here, slowness is embraced.

In fact, once you've acclimatised to the pace, this beautifully acted show taps into the undeniable thrill of a stage occupied not by high drama or raging conflict but the rarely seen everyday, or as some people call it, the truth.