Picture a world that’s dying. And the only thing that can save it is the imagination of children. In a world lucky enough to contain Greta Thunberg, this may or may not be intended as a parable but with this bright-eyed and talented cast, Limbo: City of Dreams is brimming with hope.

The production is a collaboration between the Royal Conservatoire of Scotland‘s musical theatre department and the American Music Theatre Project at Northwestern University in Chicago. Written by Scottish singer songwriter Finn Anderson, students from both institutions have collaborated to devise and then perform the piece together.

Isobel misses her mother but is nonetheless burdened with a vivid imagination that is feared rather than celebrated in the city run by The Machine. Her cheerless stepmother urges conformity and her dad’s too ill to pay much attention. But when Isobel discovers life outside the city walls and a past previously concealed, The Machine is already failing. Can her imagination save the day?

A cast of fifteen is a rarity in the Fringe and means director Tania Azevedo is able to use them to create a series of vivid tableaux with costumes, puppets, a minimal set and colourful lighting design from Neil McDowell Smith. Bursting with a fizzy energy, it’s scarcely fair to single out any individual actor but Katie Lynch as Imogen is instantly endearing. Inna Tähkänen as Chase is the sulkily suspicious then follow-you-to-the-ends-of-the-earth friend we all deserve. Rachel Hunt’s Dee is perfectly plausibly perfect. And Emmet Smith as Spark (and in-house beatboxer) is surely a star in the making.

On stage throughout is Musical Director Kalle Ruusukallio on the keyboard. Callum Cronin and Mathew McAteer double up on the bass. And David Kerr provides pacy and varied percussion. The music in this show runs the gamut from a Les Mis-worthy rousing call to arms, a Stephen Sondheim-esque discord right through to the dreamy, evocative, musical equivalent of a soliloquy, aided and abetted by the brilliant vocal talents of the cast. Alexa Moster as Reverie is a particular pleasure.

The show is playing on alternate days at the Gilded Balloon Patter Hoose on Chambers Street until 25 August. When you need a reminder that the future isn’t hopelessly lost to us, check it out.