Sean Hayes in ‘The Unknown

There’s a refrain that follows Sean Hayes around in The Unknown, and it doesn’t take much to hear echoes of The Phantom of the Opera in the way the playwright David Cale has arranged its scansion and melody. “I wish you’d wanted me,” Hayes’s character, Elliott, a playwright who’s on a digital-detox retreat upstate, hears a mysterious voice singing somewhere outside his window. “How different life would be / I’d love you endlessly / If you had wanted me.” The song is prerecorded, and it sounds a lot like Hayes is singing it. He’s the only actor onstage and remains so for the entire play, keeping us rooted in a tale narrated from Elliott’s perspective, even as Hayes adopts the mannerisms of the many other figures he describes. Though, as in a lot of The Unknown, when you hear that song played from a speaker way to the left of the audience, you start to second-guess yourself: Might another person suddenly appear? Is Elliott really so alone? How real are the phantasms we imagine chasing us?

In The Unknown, Cale has arranged a series of deft, destabilizing plot turns about the stalker who Elliott imagines is tracking him. To describe them fully would spoil the fun and take too much time, but the song Elliott is hearing is from a musical he’d written a few years back. And when he comes back to New York after his retreat, he has a chance run-in at a gay bar with a Texan who comes back to his apartment, possibly drugs him and then disappears by morning after writing those song lyrics on his body. When Elliott tries to track him down, he discovers that the man might have been an actor who’d auditioned for his musical but been rejected and that he might also have a twin brother as well as a tortured past back home. You have to keep all that in the realm of the theoretical, because Elliott’s never quite sure of his footing, nor are we in the audience sure of whether we trust him. Cale gives us plenty of reasons not to — he seems to have a drinking problem, for one, as well as other impulsive and addictive tendencies. What’s more, in a damningly accurate C-plot about how writers behave, he quickly decides he should boost his own career by packaging these events into a screenplay to sell to a studio that sounds a lot like A24.

A slippery, self-hating character like Elliott is a gift to an actor. Hayes plays him, and all the other people Elliott encounters along the way, with a showman’s delight. He’s best known at this point either for playing the clownish Jack on Will & Grace or for being the relatively serious one of the three celebrity chatters on his podcast, Smartless. He did also win a Tony three years ago for Good Night, Oscar, which depended on his pressing the persona of a familiar performer up against his character’s despair. As Elliott, he channels, alternatively, aw-shucks normie-ness and an artist’s unsettling, destructive delight in the chase of a good story. He can also nail a character in a brief gesture and a voice — by brushing away imaginary bangs as Elliott’s concerned female friend, or applying menace to the way a leering older queen might puff on a cigarette while surveilling a piece of trade.

The Unknown could use more of that menace. Throughout the production, and especially once Elliott’s circumstances start to get weird, director Leigh Silverman hits the audience with sudden, silent horror-film punctuation marks. The lights (by Cha See) will drop out and isolate Hayes in a beam of dread as he arrives at some further unsteadying discovery about his stalker. But those swerves into ominousness don’t linger, and Silverman and Hayes don’t keep us submerged for long. As a comic actor, Hayes has got the buoyancy of a beach ball, and though he can bring you to a moment of genuine unease, he’ll quickly rebound out of it at the first opportunity to land a good joke. This is your friend Sean Hayes. I could feel the audience tensing during a dark turn and releasing once he hit a punch line, an effective motion for a monologue like this to execute, as long as it’s underpinned by a deeper structure. I longed for a stronger sense of that bass line, some Dies Irae–style descending footsteps toward hell or wherever we might turn up next.

Perhaps that frustration was also informed by an awareness of some of Cale’s other work, which both outstrips The Unknown in some ways and gives the play an engaging metatextual sheen. The playwright has made a career of monologues like this one, which he’s performed himself or given to other actors (as with Harry Clarke, a multiple-personality drama Billy Crudup performed that you may think about a lot here). At the Bushwick Starr last fall, I saw Cale perform in Blue Cowboy, a new play of his about a lonely writer on a retreat — echoes of The Unknown already — who ends up in a romance with a younger cowboy, in which, again, things are not as they seem, though in a register that was more melancholy than chilling. There, many of Cale’s pet fascinations, like the precariousness of memory and the lacuna between yourself and other people, opened themselves up with a lovely quietness. Here, though The Unknown touches on many of the same expanse of themes — there’s a recurring beat, which Hayes plays well, on the loneliness of being a gay man of a certain age — Cale’s construction is tidier and neater. About halfway into the play’s brisk 70 minutes, I started to see where The Unknown had to be going by its finale, though I didn’t necessarily resent that. It’s not dissatisfying to see Cale and Hayes pull off what is, dramatic-construction-wise, a magician’s trick. But that sturdy sense of narrative determinism does shrink the play’s horizons, keep it packaged tightly, and make it consumable. It’s just the kind of thing that might sell well to a movie studio.

The Unknown is at Studio Seaview through April 12.