Just as August Wilson centered most of his dramas of the African-American experience in his home city of Pittsburgh, Samuel D. Hunter has returned again and again to his native state of Idaho to chronicle the damaged lives of its residents and those who have left, but still nurse their hurts received there. Hunter has focused on the fraught relationships between queer and straight Idahoans in affecting dramas like Pocatello, The Whale, A Case for the Existence of God (winner of the New York Drama Critics Circle Award), and his latest, perhaps most searing play, Grangeville now at Signature Theater.

We begin in total darkness, listening to the disembodied phone voices of two estranged half-brothers Jerry and Arnold (Paul Sparks and Brian J. Smith in riveting, heart-wrenching performances). As the conversation progresses and the lights gradually dim up, we learn that Jerry and Arnold have different fathers but the same mother who is in failing health (spot-on sound by Christopher Darbassie and lighting by Stacey Derosier). Truck driver Jerry has been caring for their mom in the titular town in Idaho, while artist Arnold is living in Rotterdam with his husband, a museum curator, and has not been in contact with the family for years. Jerry needs help dealing with Mom’s disorganized medical bills, but he also wants to re-establish relations with the younger Arnold. The attempts at reweaving the frayed bond between the half-siblings forms the thread of the play and Hunter sensitively explores the nature of family trauma and the need for forgiveness and coping with suffering.

Though Sparks and Smith are the only two actors, they also play each other’s partners in separate scenes. In what could have come across as a gimmick, the performers and director Jack Serio manage to make this difficult double casting work. Smith subtly plays Jerry’s ex-wife Tracy without descending into female caricature and Sparks takes on Arnold’s spouse, the Dutch Brom with surprising delicacy. But it is in their portraits of the two brothers that the pair are most shattering. Sparks compassionately limns Jerry’s guilt over physically abusing Arnold when they were kids and his earnest desire to make amends. He’s also particularly funny when Jerry tries to wraps his working-class mind around artistic concepts. Neither the playwright or the actor are condescending here. Smith taps into Arnold’s rage at the ill-treatment he received as a young gay man in a homophobic society and builds a careful scaffolding of icy reserve around this damaged soul. When that edifice comes crashing down and the siblings finally reach out to other figuratively and literally, it’s devastating.

In addition to the double-casting aspect, Sergio takes on the tricky task of the characters having to play scenes via cell phones and Zoom meetings. Jerry and Arnold only occupy the same actual space in the final scene. But Serio conquers this obstacle by having the actors relate to each other as if there were in physical proximity throughout. His understated direction and the spare set by the dots design team perfectly captures the blistering emotions evoked in Hunter’s tender two-hander.

Grangeville: Feb. 24—March 23. Signature Theater at the Pershing Square Signature Theater Center, 480 W. 42nd St., NYC. Running time: 90 mins. with no intermission. signaturetheater.org.