If only the weather was a paid-up Equity member. Then composer Stephen Deazley and choreographer Fleur Darkin, the co-directors of Helter Skelter, could have kept the rain off-stage during the rehearsal period when indoor ideas had to become site-specific in the Hidden Gardens.

For, on paper, this end-of-season Tramway commission was a terrific wheeze: one of those ragamuffin capers where the boundaries between reality and illusion blur - or maybe become one, bizarrely bonded by the pain, dysfunction, love and dreams that constantly travel with a down-at-heel circus-cum-fairground.

As dusk crept over the Hidden Gardens, Deazley's bravura band, Music at the Brewhouse, would deliver his specially-composed score from inside a giant cage, and a cast of international talents - physical theatre, circus skills and cabaret a shared forte - would beckon us into the shadowlands of the soul that Deazley, Darkin and Dilys Rose (who authored the text) saw as the hidden, secret existence of the wandering entertainers.

On Wednesday night, when I saw the piece, it was clear how close Helter Skelter had come to realising its considerable ambitions. Despite problems with the sound balancing, Deazley's score is the perfect lure: great, rambunctious swells of oompah giving way to wistful, haunting songs of yearning and bewilderment; Dougie Hudson's voice, like silvery smoke, stealing into our ears as fantastical figures, such as Birdboy (just one of Oleg Shukovsky's wonderfully wayward personas), reveal the dark side of nursery rhymes and fairy tales.

A stilt-walking dominatrix, a knife-thrower tired of his assistant-wife; their hang-ups filter through into the act as we're led down the garden's paths, but it's the indoors ending that really impresses, with its brooding atmosphere and aerial work an anthem to broken lives, and the lost and lonely travellers forever sliding, Helter Skelter.