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Tone and mood, no matter your medium, are elusive creatures. That’s why we refer to “conjuring” them, as if they were magic spirits summoned from some bubbling cauldron.

The Shakespeare Theatre Company’s current production of Camelot (cue high-treble trill), directed by Alan Paul and going on now until July 1, crosses all its T’s, dots all its I’s, and crimps all its medieval braids. Whatever your favorite song is, they sing it well. But the musical’s (admittedly scattered) emotional range — from witty humor to heart-wrenching pathos and back again — gives this cast and crew a bad case of whiplash. Story-wise, they get from A to B, and it doesn’t suck to watch, but the audience’s pleas for theatrical magic go completely unanswered, like incarnations left reverberating in an empty cauldron. It isn’t that the mood is off, more that there just isn’t much of one.

As King Arthur, Ken Clark does good work showing the character’s progression from tree-climbing young man to world-weary monarch. You never don’t believe his performance, whether he’s swinging a sword or taking a bath. He’s got a rich voice, too, though during solos such as “How to Handle a Woman” (way to go on the updated lines, by the way), he’s sometimes acting more than he’s singing. This is Lerner & Loewe, after all: It really is OK to just stand there and sing! Clark has a rollicking chemistry with Alexandra Silber’s Guenevere, who is packing some killer pipes underneath eyes that can shoot daggers all across the stage. Among the leads, she’s the best at weaving in the comedy. The rubber hits the road when Clark and Silber meet cute — they give the play its spark, and they seem to relish Ana Kuzmanic’s period costumes. And as Lancelot, Nick Fitzer opts for sex appeal over irony, though that decision is mostly made for him by the script. Belting out the so-cheesy-it-should-come-with-nachos “If Ever I Would Leave You,” Fitzer shows commitment. I hope to see all three on D.C. stages again soon.

Speaking of stages, the set and lights here seem to belong to a different play. The stately, wood-paneled scenery would well-suit a production of Hamlet or Macbeth, but for Camelot, it lends a dour air of self-seriousness. And the lights are entirely too busy — flashing with rage, shimmering from the wings, and, in one particularly unsubtle moment, pinning history’s most famous love triangle in an actual triangle of crossed drop-spots. Color me unimpressed. The costumes are largely better, except for the aggressively playful outfits sported during “The Lusty Month of May,” which, for the record, Silber crushes like an empty soda can. You can’t force whimsy.

The best and the worst of this show come out in the classic Act 2 duet “What Do the Simple Folk Do?” Silber and Clark have prepared you for this moment, building their performances well, and they dive into each verse with verve. But the song is funny when it should be sad, and downright maudlin when it should be funny. Poor Clark has to deliver the punchline while fighting back tears. It isn’t that the number, or the show, is exactly unsatisfying, but it never seems to know what to satisfy.

Any production of Camelot lies between a rock and a very soft place. There’s the legendary, untouchable original Broadway cast (why yes, the soundtrack is available on iTunes), led by Richard Burton, Robert Goulet, and Julie motherfuckin’ Andrews. And there’s the unspeakably bad film adaptation, starring a tone-deaf Vanessa Redgrave and a stack of cheesy ‘60s color filters. It might be the worst movie of a great musical ever. Shakespeare Theatre’s production clears that bar easily — you’ll leave humming the melodies. But could you describe the tone of the piece? I can’t, and I’ve seen it.

Camelot runs at the Sidney Harman Hall through July 1