Ockham's Razor, Linbury Studio Theatre, Royal Opera House, London

As a company, Ockham's Razor have made drama from the risks of aerial performance, showing characters trapped on rafts or clinging to trapezes. With their new show, The Mill, good ideas take too long to emerge from a complex set-up.

The set-up itself is impressive. The Mill takes place in an acrobat's industrial landscape. Lit by Phil Supple, white light slants through steam, across ropes, pulleys and a huge treadmill hanging in the air. The Mill's comedy and drama comes from the people working inside these elaborate systems.

One person walks on top of the treadmill, another inside. The turning wheel pulls ropes, and drives other performers, around the edges of the stage. They shout "set!" or "walk!" to start the process; a bossy recorded voice tells them to change direction, or allows them to rest.

The drama comes when the system breaks down. An extra woman blunders into the set-up, tugging on the wrong rope. Small mistakes are passed down the line, until someone is left frantically dangling, trying to scrabble back to safety. Ropes slip and unwind with dangerous speed, chased or ignored by the performers.

Other characters get lazy, making the rest pull their weight for them. They squabble over favoured places in the line: better to swing from a rope than to be the one holding everyone steady.

With such complicated systems, they have to build up to those jokes and confrontations. At its best, The Mill shows trouble passed on like falling dominoes. Elsewhere, you can see these characters working themselves up to the point of causing mayhem. The treadmill and pulleys stress the work of aerial theatre, the slog of keeping movement and balances going. But that also points out the labour of setting up these stories, of pushing the narrative onwards.

Once they get going, the dynamics are lively. A man lies on a rope, rocking as if on a hammock. He'll walk along this slack tightrope, swaying, never wobbling. Wheels roll across the floor, sometimes going right over performers: knocking them out, picking them up.

It ends with a wild breakdown: the treadmill spinning so that ropes and pulleys unravel. It should be a moment of abandon, the recorded voice breaking down as the performers escape from toil. But again, you can see it coming.

Touring to 23 March (Ockhamsrazor.co.uk)