Puppet Love: Orphaned Lili seeks acceptance from carnies while Carrot Top falls for her.

You’d think if you were an author reworking a bittersweet 1961 musical for a 21st-century audience that the first thing you’d do would be to rename your lead puppet—because “Carrot Top” just has all sorts of alarming associations now.

You’d think, too, that if you were a director reworking a 1961 musical right about the time Harry Potter is getting ready to open in the London revival of that notorious 1973 play about the boy and the horses, you’d do your very best to stage that scary number with the carny barker and the quartet of Pony Dancer showgirls so it doesn’t set the audience to tittering about Equus! The Musical. How you’d do that without getting rid of the big spangly horse-­headdresses, I confess, I don’t know.

But then, I confess, I don’t know what anyone associated with the Kennedy Center’s paralytically inert revival of Carnival! could have been drinking, I mean thinking. No, scratch that: It’s too easy, though it is pretty much how I felt coming out of the Eisenhower Theater the other night. The trouble, plainly put, is that Carnival! is an oddball show: The hero’s disagreeable, the heroine perplexingly simple, the tunes an ill-unified collection of saccharine ballad and midway oom-pah and barroom wink-nudge. And the story’s a baldly unconvincing romantic tangle involving people who have no business, ever, being in the same romantic arena.

Lili (Ereni Sevasti), the fresh-faced naif who appears at the top of the show, has been orphaned; she’s followed her dying father’s instructions and turned up at the sideshow, only to discover that dad’s souvenir-seller friend, who was supposed to take her in, has predeceased the pater. The roustabouts, the ringmaster, even the handsome, womanizing magician demonstrate a leering interest in Lili, but it’s the lonely puppeteer, Paul (Jim Stanek), who genuinely loves her—only you wouldn’t know it, because he snarls at her every time they speak.

In fact we come to understand that Paul likes Lili (who’s presumably somewhere between the “11 or 12” she seems to be emotionally and the 16ish she appears to be physically) only because after he’s done being hateful to her, he—are you ready?—retreats behind the kid-friendly personas of cheerful Carrot Top, plus a woeful walrus, a smooth-operator fox, and an imperious opera diva, all of them puppets, working overtime to ease her distress and help her make friends. Then he falls in love with her, because, of course, she’s completely guileless and likes everyone and, at one point, appears to think Carrot Top is a real person. I can’t decide if Paul’s burgeoning feelings for an orphaned, emotionally damaged teenager are just creepy or actually illegal, but they’re a hell of a thing to build a musical around.

Oh, did I mention Paul is a wounded war veteran? Who used to be a ballet dancer? Who’s nasty to pretty much everybody, including his long-suffering, open-hearted assistant Jacquot (the superb Michael Arnold), because he can’t dance anymore? It’s meant to make him sympathetic, of course, but while director Robert Longbottom and children’s author Francine Pascal were streamlining Michael Stewart’s original book, they seem to have stripped away whatever humanity endeared Paul (then played by a young Jerry Orbach) to ’60s audiences. What’s left for Stanek to make sense of (and he tries, poor man) is less an embittered artist than a mean-spirited character full of contempt for those whose creative ambitions he sees as less grand than his own; his yearning songs (“Her Face,” “She’s My Love”) seem like aberrations rather than revelations, so no matter how soulfully Stanek sings them, they just lie there.

Sevasti brings wide-eyed charm, abundant energy, and a clear, pretty soprano to the part of Lili, all of which is delightful in a sweet memory song like “Mira” but which can’t do much at all for a rattletrap number on the order of “Yum Ticky Ticky Tum Tum.” Natascia Diaz, on the other hand, is the very embodiment of Broadway brass as Rosalie, the magician’s assistant and mistress. She’s the real thing, and when she’s on, the stage comes reliably to life—and one of those times, she’s locked in a box with swords stuck through her, so I’m just sayin.’ And Sebastian La Cause, recently the preening snake-oil salesman Kodaly in Arena Stage’s She Loves Me, brings a similar (and similarly amusing) sense of self-intoxication to his Marco the Magnificent—the world’s laziest seducer, his swaggering, mock-heroic showstopper “A Sword and a Rose and a Cape” notwithstanding.

Longbottom’s production feels thoughtful—he’s thrown a bit of concept at it, painting his carny characters, even the backstage workers, with a layer of clown makeup that emphasizes their isolation from the “real” world of war and bereavement and plain old ordinary fear—and it looks terrific, with appropriately seedy sets and costumes by Andrew Jackness and Paul Tazewell, respectively.

It tries desperately hard to entertain, too, with flashy production numbers for La Cause’s Marco and Diaz’s Rosalie and even one for little, lost Lili and the roustabouts. (Tumbling and magic tricks, too, of course—though remember this is a second-rate carnival, so they’re hardly jaw-droppers.)

The one real triumph of the evening is the number that apparently has always worked—“Grand Imperial Cirque de Paris,” which is the grandiose name on the placards for Paul and Lili’s tatty little touring troupe. Jacquot, thrilled by the news that the Paris booking agents are coming to check out Paul’s suddenly successful puppet act, opens a big trunk marked with the name of the capital city, and a kind of dream circus takes over the stage for a few dazzling moments. It’s a vision out of the troupe’s dreams, out of the better days it probably never had, out of its imagined future, and it’s stupendous—and then it evaporates, vanishing like smoke back into that unexplained and inexplicably magical trunk. And there on the stage are Paul and Lili, Marco and Rosalie, with three songs to go and no real reason for us to care.