Like freshly spun cotton candy on the boardwalk during summer, the new musical Unlock’d is sweet and delicious yet leaves you wanting more. The music and lyrics by up-and-coming songwriting team Sam Carner and Derek Gregor have a sweeping romanticism to them, but none of the tunes ultimately satisfy.

Presented by Prospect Theatre Company and now playing at The Duke On 42nd Street, Unlock’d is clever and enjoyable, just featherweight. Audience members will remember little aside from a strand of hair that talks (and sings). The real reason to see Unlock’d is for the charming performances of its gifted cast, many of whom are talents to watch.

This winner of "Best of Fest" in the 2007 New York Musical Theatre Festival and the Richard Rodgers Award recounts the story of neglected stepsister Clarissa overshadowed by her prettier, blonder sister Belinda. Similar to Samson’s long tresses, Belinda’s golden locks are the source of her power — over men. Much to the chagrin of her stepsister, she is the most adored woman around, leaving Clarissa to wait anxiously for her own chance at love.

Set in 18th century England and taking its cues from Shakespeare’s comedies and romances with its fantastical characters (The Tempest), courtly maidens and gentlemen (Love’s Labour’s Lost), and a strained sister relationship over potential suitors (Taming of the Shrew), the main character Clarissa even speaks many of her lines in rhyming couplets (Romeo & Juliet, Midsummer Night’s Dream).

Much like the mischievous servants in classic comedy, Unlock’d throws in fairytale sylphs and gnomes to propel its narrative of star-crossed lovers and farcical misunderstandings. And the whole shebang ends with everyone in the cast of characters pairing up — again, a nod to the tenets of comedy.

A multitasking six-piece band of strings both unplugged and electric, led by pianist Adam Wachter, cranks out the operatic-like Carner & Gregor tunes, more reminiscent of Rent by Jonathan Larson than Cinderella by Rodgers & Hammerstein. Standouts include “All at Once” and the stirring “Finale,” which gleefully refashions melodies from Act One highlight “Off to the East” and is the sole spine-tingler in a show that could use more such transcendent moments before its final curtain.

As said earlier, the performers are all superb, glorious of voice and working hard to overcome the bad jokes of the book (for example, the malapropism-spouting gnome and the puerile nomenclature of the court gentlemen). With so many characters jammed into a still overly long two and a half hours, however, many of the actors get shortchanged.

Jennifer Blood as the confusingly mean-spirited heroine Clarissa carries the weight of the story as an actor, but is underused vocally. Sydney James Harcourt as the dashing yet dim Baron Roderick Shearing (another unnecessary pun) and the adorable A.J. Shively as Edwin, his bookworm brother, are both excellent, although they sometimes struggle with their upper registers in the multi-octave musical numbers. And Hansel Tan as the lovelorn Barney has one of Unlock’d’s most affecting moments with the tender and tuneful “Only a Gnome.”

Stealing the show is Jillian Gottlieb as the harebrained Belinda whose crystal-clear soprano brings down the house in every one of her numbers. Gottlieb locates an authentic naïveté in her character that could otherwise have been one-dimensional. Her “Hair Song” — with vocal harmonies provided by her beloved ringlettes — is the funnest and funniest song in the show.

I would be amiss not to single out Amy Clark’s fetching candy-colored costumes, particularly scrumptious for the maidens and gentlemen of the court, mirthfully and enthusiastically played by a sextet of actors who do double duty as the fantastical sylphs and gnomes.

With a little pruning, Unlock’d might be able to fully unlock its own potential and become the fairytale musical it hopes to be. It has all the right elements, but needs some rejiggering and the addition of at least one true showstopper. As is, it simply doesn’t make the cut.