Power Plant consists of 22 sound and light installations by five artists threaded through and around the glasshouses of the Royal Botanic Garden.
We enter the shadowy garden through a theatrical proscenium arch of hedge. As the audience see the glow of the towering palm house the walking pace picks up - whether drawn to the hypnotic light or just to get out of the torrential rain, I am not sure.
Stepping inside is like going through an airlock onto an alien planet. There is something that looks like a base camp, a huge air raid siren standing ominously in the centre of the clearing. The crowd splits up into little groups to investigate the sources of strange sounds. You just know that if this was Star Trek, the guy in the red shirt would not be coming back.
On we go, tentatively pushing through rainforest where mirror-balls create a million fireflies, past a tree crackling with Taser-like sparks, and out into a clearing of giant musical garden torches that pop and burble with gas flares, sometimes syncopated and occasionally flashing into a long arpeggio of flame.
"Amazing!" someone near me murmurs.
Past a tinkling zoetrope of fire and back into one of a series of long glasshouses, where there are whirling flower-shaped blades of light accompanied by a helicopter like whump.
For all its delicate beauty, it reminds me of Apocalypse Now and leads me to interpret the next installation of torn floral dresses as being shredded by shrapnel. But that's just me and that's the thing - there is no narrative here and it's intended to be experienced as a whole, with one piece leading to the next. You are free to explore and spend as much or as little time as you want in contemplating each section.
The lack of live action makes it a relaxed affair and it's strangely calming after the madness of a day on the Fringe. Many of the works are relatively low-tech and have a wonderful Heath Robinson quality - like the suspended corridor where you can rest beneath standard lamps that talk to each other in theremin twitters.
By an Amazon pond an audience member takes photos of his girlfriend as she smoulders beneath a bower. A few minutes later I see her take close-ups of a giant phallic plant. It appears that there are perhaps fairies at the bottom of the Garden dispensing "love-in-idleness" too.
On the way out into the waiting dark there is a comment book. One entry reads: "The best thing I have seen in the Festival. Perfectly brilliant".
Times: 12-16, 19-23, 25-30 August, timed entry every 10 minutes from 9.30pm until 11.15pm. Closes midnight.
Note - Access is by the North Gate on Inverleith Place.