Tom Cruise is on lead vocals as an ageing rocker in a stage-to-screen musical that rocks to the perm-shaking Eighties sounds of Styx, REO Speedwagon, Journey, Pat Benatar, Twisted Sister, Poison and Whitesnake. It's Hollywood in 1987 and a smalltown girl (Julianne Hough) falls for a young muso (Diego Boneta) while working in a muso dive. Also raising a tune are Russell Brand, Catherine Zeta Jones and Paul Giamatti.
Our smalltown girl living in a lonely world is Sherrie (Hough), who has travelled from Oklahoma to Los Angeles with dreams of becoming a star. Immediately on arrival however, her suitcase - filled not, it seems, with clothes but with her favourite records (of course - who needs clothes when you've got music?) - is stolen on Sunset Boulevard. Are Sherrie's dreams shattered?
Of course not. The dishy Drew (Boneta) arrives just in the nick of time to chase after the thief. He doesn't get her belongings back, but he does help her get a job as a waitress in The Bourbon Room, a local dive where some of the great rock legends were launched. Drew's a wannabe singer too. Naturally, they get it on.
But there are obstacles to stardom beyond Drew's big hair and Sherrie's charming naivety. The Bourbon Bar is on the brink, the city mayor is trying to stamp out the sex, drugs and rock 'n' roll lifestyle pervading the strip and there's a new-fangled thing called "boy bands" that might kill off rock for good.
Rock of Ages was never going to be great drama, but it has lost some of its energy in translation from stage to screen. Or perhaps it is the fact that it doesn't feel translated at all.
The film feels episodic in just the same way a musical often does, jumping from song to song with little regard for narrative realism - but without the buzz of live performance.
The music's undeniably fun - featuring tracks from Poison, Guns N' Roses and Foreigner - but the whole things feels a bit piecemeal, in particular the one new addition to the script, Zeta-Jones's ball-breaking first lady of Los Angeles, who's barely given an introduction before she's belting out a ballad.
Similarly, Mary J Blige appears as a helpful strip club owner, is given a big number and then is off again almost straight away.
Even Russell Brand, who is wheeled out in much the same guise as Get Him to the Greek but with a bad Brummie accent, is a little lacklustre, although his buddy chemistry with Alex Baldwin's weary club-owner Dennis is spot on.
Tom Cruise, on the other hand, is a sweaty, seductive revelation as ageing rock god Stacee Jaxx - and makes up for a fair amount of lethargy elsewhere.
We haven't seen him have this much fun since Tropic Thunder, as he puffs up his chest, owns Bon Jovi's Dead or Alive and romances groupies. He writhes manically on stage, returns cutting quips to lesser mortals and manages to tread that very difficult line of appearing wasted without going slapstick. He is magnetic.
The rest, though, is largely fluff... fluff that, when the music stops playing, lacks the likeable camp of director Adam Shankman's previous effort Hairspray.
Somehow the film feels more like it belongs to the boy bands its protagonists so fear than the rock idols they yearn to be.