When a show like “The Bogus Woman” comes along, strong and documentary but as ephemeral as a newspaper page, it can be a trick to figure out just how to praise it.

Kay Adshead’s play, a monologue performed by the chameleonic Sarah Niles, serves as an expose of the British policies on asylum seekers. Ms. Adshead’s story has gathered threads from dozens of true accounts, which makes the piece a kind of hybrid. It wants to throw a sucker-punch with the horrors of actual events, yet it also claims the privileges of fiction.The playwright can shape her poetry to the allotted time, finish plot points off as neatly and poignantly as possible, and collapse a host of injustices into a single life. What she trades away, however, is her piece’s most direct claim on our emotions.

Just off the plane in Heathrow, a young woman suffers a mental breakdown. She is unnamed, as is her African homeland. Confused and vulnerable, she can’t maintain her disguise as a carefree tourist. It’s a matter of seconds before her false passport damns her to the Campsfield detention center for asylum seekers, where all the weight of British bureaucracy will try to squeeze her into a confession. Every guard and Home Office interviewer assumes she is a “bogus” refugee, in London to steal jobs rather than escape persecution. They pick through her traumas like bargain hunters at a sale, holding them up to look for holes.

The young woman’s horror stories begin to blur and fade into one another. In Africa, after she wrote political pieces for a newspaper, thugs in uniform killed her family and baby in front of her. She was forced to hide in a cellar, drinking rainwater, until she escaped – directly into the stony arms of English hospitality. Racist, inhumane treatment at the center, an overworked lawyer, and a collapsing sense of agency conspire to destroy her again. She has survived rape and violence, but bureaucratic callousness will prove an equally efficient assailant.

Ms. Niles plays more than 40 characters, gracefully shifting between interrogator and victim, neighbor and killer. “Look out, Sarah Jones,” murmured one audience member as we shuffled out, and Ms. Niles easily equals the “Bridge and Tunnel” star’s facility with expression and accent. Director Kully Thiarai gives her only a bench and a bag to work with, never letting Ms. Niles outside a six-foot square space. Even when the woman receives temporary admission, a six-month reprieve to make her case for asylum, she still moves like her world is a cell.

It’s an Amazonian performance, and thrilling to see a talent like Ms. Niles unleashed. She does grave justice to Ms. Adshead’s flights of poetry, moving through them so effortlessly, we never hear the stanzas break. Still, it’s difficult not to leave feeling as though a duty has been performed. Certain tiny distances add up: We know the young woman is a composite figure, which saps it of its documentary power. And American audiences can leave feeling smug. If only we were hearing the same tales out of our own justice system, we might feel the keen edge of guilt and rage. Instead, it is blunted by distance and our own unthreatened illusions. “The Bogus Woman,” therefore, excels as a news bulletin, but falls short as a play, falling right in the middle of the mess of categories we call the theater.

Until May 21 (59 E. 59th Street, between Fifth and Madison Avenues, 212-279-4200).