What a taut and skillful thriller “Rope” is. Patrick Hamilton’s 1929 play, now at the Zipper in a Drama Department. revival, holds up surprisingly well after 76 years of intervening crime dramas. Over three acts, “Rope” teases out a story that no crime show today would give more than a half hour, luxuriating in character details and prolonging the gooseflesh (it’s easy to see why Hitchcock wanted to film it). Under David Warren’s competent direction, Hamilton’s calculating drama moves from point to chilling point. One has the sensation of being marched over a mountain pass – with periodic halts to peer over the edge from a dizzying, terrifying height.

“Rope” begins with a murder in the dark: the strangulation of an Oxford undergraduate by two of his classmates, who quickly stuff him into a wooden chest. The first of the spoiled boy-murderers, Brandon (Sam Trammell), is exhilarated by success; the other, Granillo (Chandler Williams), is terrified of being caught. Earlier, as a sick sort of finishing touch, they planned a dinner party, which is set to begin in a quarter of an hour. Now Granillo’s conscience quails before the prospect of serving dinner on that wooden chest. “Have we not already agreed,” Brandon says, “that the entire beauty and piquancy of the evening will reside in the party?”

These boys have murdered dispassionately, as a kind of Nietzschean sport. To them, the body in the trunk is proof of their superiority to the rest of the human race. The party is a chance to gloat – and to certify their brilliance by duping an old family friend who is the only man they consider smarter than themselves: Rupert Cadell.

The middle-aged Rupert, as splendidly realized by Zak Orth, limps around the room on his wooden leg, self-conscious and proud. He puffs out his chest and moves his plump neck in supercilious little circles before he speaks; given his tuxedo, he looks like a penguin. Rupert’s compensation for being unattractive and lonely is his razor-sharp mind. He’s a very good thinker who claims to (and probably does) write excellent poetry. But at parties, he brutishly levels his caustic wit on everyone within earshot – even a sweet, nearly deaf old aunt.

Hamilton’s genius as a playwright was to make Rupert a prig with a heart, to gradually scrape back the layers of misery and uncover his surviving humanity. The transformation begins with Rupert musing on the killing he did in the war, and gains force in a beautiful speech about the pathos of London at 10:35 in the evening. It culminates in Rupert, the reluctant detective, who so wants to be wrong, finding the courage to confront the boys. At the moment of discovery, Rupert, who has earlier mocked Carlyle for his “angry righteousness,” is seized by rage and grief. Throughout the journey, Mr. Orth’s bravura performance lets us see into Rupert’s soul: its vanity, its melancholy, and finally, its vigor.

There are objections to the production, to be sure. The set – more flea market Zipper than carelessly rich Mayfair – fails to capture the boys’ extravagant, indolent lifestyle. And the boys’ homosexuality, long treated by productions as a quivering inarticulate tension, is handled here in the most pedestrian way – with hugs and kisses. The point is not, it seems to me, whether audiences will tolerate the openness, but whether these 1920s gentlemen would have embraced (as they do now) in front of Rupert Cadell; I think not. Moreover, the choice deprives the actors of some very fertile subtext – and negates the power of Brandon’s last-ditch effort to throw Rupert off the scent by outing himself and Granillo.

But “Rope” is so exquisitely constructed that simply watching the performers serve it is an enormous pleasure. Rarely has dramatic irony been so deliciously deployed as when the butler clears the dishes from the wooden chest. First he takes away the glasses, then the plates. Finally, he folds up the tablecloth, and the squeamishness is almost unbearable. “I have gone all out to write a horror play and make your flesh creep,” Patrick Hamilton wrote in his preface to “Rope.” “If I have succeeded, you will leave the theater braced and recreated, which is what you go to the theater for.” Three-quarters of a century later, “Rope” is still provocative, terrifying, and finally, affirming.

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