Book and lyrics by Keythe Farley and Brian Flemming. Music by Laurence O’Keefe. Directed by Peter Jorgensen. Presented by Patrick Street Productions. At the Norman Rothstein Theatre on Friday, April 9. Continues until April 18

Bat Boy: the Musical is about as consistent as a bat’s flight path. There are great moments in this show, but it’s all over the place.

Inspired by a 1992 story in the tabloid Weekly World News, Bat Boy tells the tale of a half-boy, half-bat, who gets rescued from a cave deep underground in West Virginia. When the sheriff takes the orphan to veterinarian Dr. Thomas Parker to have him euthanized, the vet’s wife, Meredith—who names the creature Edgar—convinces Thomas that they should keep him.

The other locals are less charmed. Redneck Christians, they blame Edgar for the lingering illness of a young woman he bit while still in his savage state, and for the strange malaise that’s affecting local cattle. Their suspicions aren’t unfounded: Edgar has a taste for fresh blood. The central tension in the story is whether anyone will fully accept this flawed, unsettling creature as human.

This synopsis might sound promising, but the problems start right off the bat—so to speak. The opening scene, in which the strange beastie is discovered, is boring: the West Virginian yokels who find him are so broadly—and flatly—stereotypical that I’m surprised nobody has sued. No engaging relationships are established in the early going, and the music is dull, as it is throughout almost the entire piece. It’s not until Meredith sings “A Home for You” to Edgar that the musical gains any traction—and that’s five numbers in.

From that point on, Edgar’s human personality starts to emerge, and he’s a treat. In one of the book’s most satisfying conventions, Edgar learns to speak English from BBC tapes, so he acquires a British accent. The juxtaposition of Edgar’s gentle, Leslie Howard delivery and his pointy ears and teeth is weirdly endearing.

And Scott Perrie’s performance as Edgar is excellent. Perrie makes Edgar as innocent and bestial as a puppy—all wide eyes, open heart, and fangs. There’s delicacy and depth in this characterization, and Perrie is a tremendous singer, always sure of his pitch and vocally strong throughout a wide range.

Still, Act 1 mostly fizzles. Despite the show’s self-conscious strangeness, the first half contains very few surprises and, overall, the musical is thematically obvious: we should accept the beast within.

Fortunately, Act 2 has a couple of great tricks up its sleeve. We get to meet a certain cloven-footed creature—I won’t tell you who or how—and a parody of old black-and-white movies is used to fill in Edgar’s lurid backstory. There are a couple of memorable songs in the score, including the tent-meeting number “A Joyful Noise” and Edgar’s mournful ballad “Let Me Walk Among You”.

Katey Wright (Meredith) is in fine voice, as is Bree Greig (Meredith’s daughter Shelley), which makes their second-act duet, “Three-Bedroom House”, a pleasure. Most of the cast is vocally solid, but despite delivering a tremendously witty acting performance as Thomas the vet, Scott Bellis hits some scary high notes and his pitch wanders.

Speaking of scary, I feared for the limbs of the actors as they negotiated the stairs on Julie Martens’s set. That was distracting. On the other hand, Amir Ofek’s costumes are a delight.

This show would be a good deal if you could pay half price and just see Act 2.