It's easy to see why the Riot Group has made such a splash at the Fringe in previous years: its plays, written by co-founder Adriano Shaplin, are driven by a bracing intellect, which can feel like a rare commodity here. This year's offering recalls the moment when the US discovered technology: when gossiping, flirting switchboard operators were replaced by automated telephone systems, rendering these people - and, by implication, humanity - redundant.
This is undeniably a moment in history laden with pathos. The play is set in 1919, and we can see in the treatment of its three female operators the seeds of the boom of the 1920s, as corporations exploited the means to unprecedented wealth, and also the depression that would follow. The trouble is that Shaplin doesn't so much work on his audience's emotions as bully them. In the contest between Lucille, a sharp-mouthed Italian immigrant who thinks of herself as the archetypal tough American, and Jane, an Englishwoman determined to fight the new regime through the union, Shaplin presents not characters but mouthpieces. And what they tell us - that New York is a fierce town and that Americans are disturbingly suspicious of organised labour - is hardly new enough to justify our being hectored.
· Until August 29. Box office: 0131-226 2428.
