Baddies: The Musical (Unicorn Theatre)

Nancy Harris and Marc Teitler’s new musical is ‘brilliantly conceived’ but lacking in plot

Think Into the Woods meets Assassins. Baddies: The Musical is a mash-up of malevolence – the fairytale equivalent of the Injustice League, in which a whole bunch of villains slammed together in a single story.

Nancy Harris and Marc Teitler's musical is brilliantly conceived, no doubt about it. Not only because bad guys (and girls) get all the best lines, but also because bad guys (and girls) get a bad rep. Giving them stage time, making them masters of their own story, turns the tables, and Harris and Teitler set about challenging the dominant narratives we press into our children: that good little boys and good little girls and pretty little bland things win out in the end. It's lit crit for little critters, basically – and you can bet your kids won't think of stories in the same way again.

On the orders of the Council of Bedtime Stories, all the baddies have been rounded up – a sharp critique of a jail-happy judicial system and anti-terror laws. Stuck in a cell together, however, they get to talk freely, and Harris and Teitler start to unpick our assumptions about them.

First, they humanise these characters, providing motives for antagonism. The Big Bad Wolf (Dean Nolan) is just doing his job. He's really a nice guy with a temper, and the Ugly Sisters (Claire Sundin and Kelly Agbowu), they're fed up of being overlooked. Then, they find virtues underpinning their villainy: Captain Hook's taste for adventure, Rumplestiltskin's mathematical genius. There's a wry, ironic humour in all this ("I'm a baddie, but I can still feel for other people," whines the Wolf), but all of a sudden, you've got complex characters – each a mix of good and bad traits, each doing the best with their lot – rather that two-dimensional evildoers.

What Baddies is missing, however, is much of a plot. After a talky-talky first half, in swoop Cinderella and Peter Pan (Kathy Rose O'Brien and Christian Roe) – one all hair-extensions and chiffon; the other a one-man boyband with a synthetic smile – with a rehabilitative rebranding programme. It's worked wonders, so far. The Snuffalo, for example – a baddie so bad he eats other baddies for breakfast (Goldilocks used to have four bears) – is now the Fluffalo, the best-selling kids' book since Harry Potter. Will the Brothers Grimm gang sign on?

Harris's book leaves a few loose ends – the Snuffalo, deployed as a threat, simply disappears – and Teitler's music is mostly pretty plodding. Baddies is sustained by witty lyrics and decent jokes, but a tighter script would make a huge difference to Purni Morell's production – especially as a story about good stories.

Instead, it's a character piece, fun but flawed. James Button's clever costumes turn fairytale characters into criminal sorts, so that David McKay's Rumplestiltskin is a pixiesh punk and Miles Yekinni's Hook, a pinstriped crook. Nolan's hairy biker Wolf is a particular treat – a gentle giant with an inner-Hulk – and Sundin and Agbowu's Sisters make a feisty feminist duo. Ultimately, though, Baddies is a mixed bad – a blend of good and bad.

Baddies: The Musical runs at the Unicorn Theatre unitl until 24 December.