Ideas for a short horror story?

I am entering a writing contest, I have started drafting, but I just need some ideas to kick start
It will be more phycological thriller than horror, not loads of gut and gore, mainly focusing on mystery/description/suspense/characters
Set on the moors in cornwall
Around 10-15 pages long
If you are familiar with the author Sonya Harnett, I am writing in a style a bit like hers
It's the plot I am struggling to string together, I have characters and descriptions etc.
Any thoughts appreciated, thanks!