I mulled it over a lot, and eventually wrote about five different endings! In the end I decided just to leave it open, with my kidnapper mulling the idea that she was going to do more to her victim tomorrow. I thought it was a bit more subtle and horrific, suggesting that she's just going to keep him there indefinitely, inflicting day upon day of torture on him...

Anyway, if anybody is interested it's just been submitted and should appear shortly. It's called "The Prey".