You could call “The Immaculate Room” the ultimate lockdown movie, or maybe the spa version of “Saw.” It’s a chicly austere and, at stray moments, provocative tabloid thriller in which Kate (Kate Bosworth) and Mikey (Emile Hirsch), as part of a mysterious contest, agree to spend 50 days living in a large bare white room. When they first walk in, they’re greeted by a Siri voice, British and female, who makes ritual pronouncements like “It is evening. Enjoy your stay in the Immaculate Room.” If they make it through all 50 days, they’ll get $5 million in prize money. (If only one of them makes it, the reward gets reduced to $1 million.) It doesn’t sound all that hard, like two months of voluntary prison time minus the dirt and danger. And that’s the hook: Who wouldn’t do this for $5 million? But the fact that it sounds so do-able means the audience is asking from minute one: What’s the catch?

In a funny way, “The Immaculate Room” is a parable of boredom, which makes it a story for our time. Kate and Mikey have a flat white bed to sleep on, but mostly they’ve got white walls and nothing else. The place looks like an empty art-museum gallery (you can just about see the Gerhard Richter paintings that would be hanging there), or an unfurnished boutique condo designed by Steve Jobs. A small milk container marked FOOD sits in its slot like an Apple product. In the container is a gooey flavorless liquid: sustenance stripped of pleasure. “Not exactly Shake Shack,” says Mikey after taking a swig. Eating is no fun, but more than that there’s no diversion. In prison you can read a book. “The Immaculate Room” is a movie made for a world of people fatally addicted to entertainment that asks: What if you had none? Would it gradually drive you nuts?

So what is there to interest the audience? For starters, there are two lively actors, dressed in designer surgical scrubs (olive green for her, rust for him), playing out the soap opera of Kate and Mikey. Hirsch, more dynamic than he used to be, makes Mikey a spoiled, surly hipster brat of an artist with a chip on his shoulder about his vegan lifestyle. He seems to resent others, but when he finds a bug in the room he’s desperate to feed and nurture it. Bosworth’s Kate is more modest, grounded, and controlling. She starts each day with a twelve-step prayer (“My name is Katherine Frith and today’s my day”) and meditates in the Sukhasana position. But she’s a New Age materialist. She wants that $5 million and is committed to the high rationality of doing anything it takes to get it.

The two have a troubled relationship, and going in on this contest seems to be their attempt to heal it. Talk about a doomed plan! As soon as we learn that the contest was designed by a billionaire scientist, Professor Voyenne (if this movie were the less spartan version of itself, he’d appear on a video screen and be played by Woody Harrelson), we realize that Kate and Mikey are guinea pigs in a Skinner box who are living out someone’s idea of a behavior-mod experiment.

There are times in “The Immaculate Room” when we feel just like the two of them: stranded in a land of nothing, wondering how we’re going to get through the next moment and the one after that. But the film’s writer-director, Mukunda Michael Dewil, knows that he can’t make a drama about monotony that falls victim to the imitative fallacy. So he introduces external elements, which is a nice way of saying he’s cheating. Kate and Mikey are allowed to buy two “treats,” surprise packages that will relieve the tedium. They’re expensive (the first one shaves $100,000 off the prize money, the second $250,000), and the first treat is just…a green crayon. (To Mikey the artist, it’s a gift.) But the treats grow wilder from there. At one point a pistol appears out of nowhere. It should have come in another Apple box, this one marked “Chekhov’s gun.”

“The Immaculate Room” starts out as a parable of boredom and ends as a parable of greed. Yet ironically, it’s most interesting when it is about boredom. When it turns into “The Treasure of the Sierra Madre” remade as a claustrophobic reality show, it becomes banal. In the end, the audience has to answer the question that’s put to the characters: Do we care more about the $5 million or them? I confess I wound up with the wrong answer.