Adam Harley in Jelly Beans
Adam Harley in Jelly Beans

The Edinburgh Fringe is usually full of visceral one-man storytelling shows – and while it's not a form that's especially overrepresented in 2017, Jelly Beans is a classic addition to the genre. A violent, high-energy monologue, it's the first full-length play by Dan Pick, who directed the fringe hit BU21.

The writing is vivid and memorable, fizzing with the energy of a sugar rush or adrenaline high. A young man from Port Glasgow, played by Adam Harley, narrates his day – but given he starts by telling us "I know what a dead body smells like", you can bet it's not going to be a tale of cheery whimsy. There's something a bit off here too in the repeated mentions of teeth. In between watching porn (he likes looking at girls with braces) and going to buy Pop Tarts, he thinks tenderly about his girlfriend Jess, and about childhood birthdays and his little sister. Flashbacks, naturally, hint at something awful that happened in his past.

Harley gives a wild-eyed but seemingly open-hearted performance, bouncy and childish and keen to engage. There are moments of fierce emotion – when he describes the "mad electric love" he feels for his girlfriend, you believe him. But it's always also just a bit off-centre, on-edge, much like Pick's writing.

Situations develop. A disenfranchised young man, promised the earth – he was told he was a beautiful child, the one other kids' parents loved best – and inheriting nothing except painful memories, there's a sense of someone teetering precariously. This psychology could either be developed more or more sharply sliced; as is, Pick seems unsure whether to offer backstory and justification or keep things fleet and mysterious. The writing certainly isn't above being look-at-me crude, either – when the protagonist talks about fingering himself in the arse while jacking off to porn he asks "how many fingers before you really hate yourself?" Jelly Beans is billed as a male Fleabag, but it's an altogether stranger beast than that.

There will be sex and drugs and cheery, irrationally vicious acts of violence before the show is out; the whole thing is sluiced with blood and cum. It perhaps tries a little too hard for the off-kilter psychopathy of, say, a Philip Ridley or Mark O'Rowe play. "I think I hate people – and I think they know it," he tells us with a grin.

But it still makes for a propulsive, compulsive hour's viewing, motored by a relentless performance as the character charges wildly through the town and towards the ocean. And genuinely unsettling are the evocative sensory descriptions that vein through Pick's writing, occasionally beautiful but more often icky, in a way that gets under your skin. You can almost smell the rot he speaks of.

Jelly Beans runs at the Pleasance Courtyard until 28 August.

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