word flow issues

I have a story to write. But it just doesn't want to get writ. It's started. It's sitting there looking for its detail and development and pretty description and intensity, all ready to be wrapped up in rope and nicely presented, and it just doesn't want to get written. I don't know quite why I'm frightened of it. I'm always a bit frightened of stories, but it's usually just a question of knuckling down and spewing out and then making someone tell me how to edit it properly. But this time it's froze. I even asked someone who does the thing that takes place in the story to tell me all about it, and she did, beautifully, but still nothing's grabbed my by the ear and pushed me into the chair and forced me to get it all out. It's sitting there, feeling uncertain. I suppose I should just let it percolate some more, and wait til the next call. Well, the deadline's already a month in the past, so... really, I don't know who I'm kidding. And now... back to correcting juvenile compositions.