First Night: High School Musical, Edinburgh Playhouse

It's a phenomenon and a puzzle. After the smash-hit High School Musical – a Disney satellite channel TV movie aired in 2006 – came the quadruple platinum No 1 soundtrack, the fastest-selling TV movie on DVD and an entry in the Guinness World Records.

Disney's High School Musical had captured the imagination of children held spellbound by this spectacle of song and dance. Almost inevitably came High School Musical 2, while High School Musical 3 is due to be released in the autumn. And after HSM The Ice Tour slid on to the scene, a video game followed.

Now comes a new stage version, adapted by David Simpatico, on the road for a 31-date UK tour which will be complemented by a second stage production opening in London's Hammersmith Apollo. Only if you live on Mars, it seems, could you be unaware of this mounting High School fever. Owing more than a little to the high-school movie genre of Grease and Fame, High School Musical focuses on a school romance, and tackles a moral issue. In this case the message, through such catchy numbers as "Start of Something New", "Stick to the Status Quo" and "We're All In This Together", is to assert your own identity and personality rather than be pigeon-holed and boxed in by the perceptions of others.

At the packed Edinburgh Playhouse – which hosted an ambitiousamateur production last summer – kids as young as three were clearly loving it.

For "Greasers", read "Jocks" and "Brainiacs", the polarised cliques at East High School, whose identity has a crisis when ace basketballer Troy and studious Gabrielle succeed, against the odds, in breaking away from their peer groups to audition for, and be awarded, the star roles in the school musical. In Jeff Calhoun's fast-paced production (the story unfolds in just a week), Ashley Day and Lorna Want make a touching central couple as Troy and Gabriella.

They're staunchly supported all round, notably by their mates played by Carlton Connell and Hannah Levane, and by Claire Machin's stentorian Ms Darbus and Helen George's Sharpay (after the Chinese fighting dog shar-pei, of course).

The athletic movement is well choreographed by Lisa Stevens, and Kenneth Foy's simple butinventive sets are moved seamlessly by members of the ensemble company.

The proposed high school musical is Juliet and Romeo and we're told that this "feminist re-write" involves a happy ending. HSM too has a happy ending, with a plot so anodyne, situations so predictable, and characters so impossibly one-dimensional that there is nothing that could possibly offend an audience.

Except perhaps the clean-cut gloss, the slim and easy-on-the eye line-up and the none-too-subtle typecasting which has the student composer as a bespectacled geek and the machinating drama queen as a Cruella de Ville of the Thespians. But the tweenies around me just giggled when she snarled that she'd "like to suck the mucus from a dog's nostril till its skull caves in".