Cardiff's Buffalo Club is small. It fact, it's bijou. Even so, Marissa Nadler still manages to look as lost as though she were in a stadium.

I watch this slender, delicate creature dressed all in red as she tunes, re-tunes and fusses over her stage-sound as a form of anxiety displacement. She is fastidious and mouselike and as she gazes out over us with searching, worried eyes, I'm wondering if she will survive the night, let alone make it to the end of her set. Once she has arrived at a passable level of contentment, she begins.

She stops.

Feedback and vocal monitor problems are upsetting her, and the guy on the desk shouts tersely "What now?"

"Give the girl a break," I'm thinking. "She's only been in the country for five minutes and she's jetlagged."

She begins (again) with 'Mr John Lee', which carries the story of a light hearted affair that takes a seriously grim turn. With the unfolding of this story come signs that the little girl before us is beginning to unfurl too. Her second song, 'Virginia', details the Bloomsbury writer Woolf's suicide. As her song and its weight subsume her, Nadler starts to peep out of her shell and before long, her persona leaves that of the pretty little mouse behind to relaunch as a blossoming woman of gravitas. The transformation is as remarkable as it is unexpected.

'Under An Old Umbrella' is the most breathtaking song on 'The Saga of Mayflower May', her newest album, and as she plays it I feel the hair on my neck stand on end as the careful picked guitar accompanies her solo voice, one that overflows with expression but at the same time is deftly held in check by the poise of restraint.

Around me, many fall under the aura of this striking woman in red who crept up on us unannounced. Nadler specialises in murder ballads where beauty, tragedy and loss are the unavoidable fates befalling all the lovers of the age. She portrays her heroines through the aloof styling of her voice and a demeanour that clamours for what is lost, whether an unfulfilled glance of bliss or a lover never to return. An exciting introduction to where Nadler will go next is 'Flora Barone, Queen of The Vaudeville Throne', which concerns her newest song character whom she plans to develop. This trembling apparition of a song has been doing the rounds of late as a session track and magazine cover mount and is even more luscious in the real.

For a slight young New Yorker with concealed depths, Marissa Nadler is a fascinating prospect but one who admits to being ill at ease with performance. Take advantage of her current intimate tour as it would appear to be far from certain whether she will manage to cope with all this anxiety again.