The award-winning Penny Dreadful return to Edinburgh this year with a curious but highly original show chronicling the advancement towards pain-free surgery and the birth of anaesthesia.

Three dentists - one, a power-hungry madman hellbent on success and money; the other two consumed with the idea of a scientific breakthrough that will truly change the world - inhabit America in the nineteenth-century, a place which inspires ambition that comes with a heavy price to pay.

As a concept, it is wonderfully novel, and even though stylistically it is a very mixed bag, there is enough here to entertain everyone. The cast are uniformly excellent. Dennis Herdman shifts from malevolent, cackling William Morton to a grotesque Mrs Wells, with a cartoon-esque humping routine winning shocked laughter from the audience.

Personally, my favourite was the shock-haired Denise Kennedy whose rubber-face and croaky tones had me in stitches as she mined a rich gallery of ludicrously funny characters, and pitched them to perfection. Occasionally, though, clarity is an issue, with almost too many roles for our frenetic three.

The creaky, Victorian-style wooden marquee is ideal for such a macabre show that encompasses shades of vaudeville, carnival and cabaret. This is shamelessly gothic entertainment, often masquerading as darkly Dickensian drama, complete with a back-lit mutilation sequence, farcical sound effects, and a heart-stopping moment where we believe an actor has been stabbed through the hand. It threatens to reduce in speed and interest as we near the concluding scenes, but picks up with a deeply unsettling look at the consequences of their obsessions and petty rivalries.

Deliciously inventive, educational, bawdy, aesthetically pleasing, and comically sinister, this show definitely will not be to everyone's taste. However, I was swept up in the old-fashioned but beautifully crafted showmanship of Penny Dreadful and their ominous study of dentistry.

- Adam Elms