ok.. so it's a 1 gallon batch, where did your recipe come from?
.. usually with fruit wines you would add pectolase ( enzyme) that will help the wine clear and you'd also add a campden tablet to help kill any wild yeasts and bacteria and some yeast nutrient. Perhaps a little citric acid or acid blend and a bit of tannin.
couple of questions..
have you strained the plums out of the wine and apart from being very sweet, does it taste ok? Where are you fermenting this?.. an area that is too cold or too hot will stop a fermentation temporarily til you move it into a temperature that is more favourable to the yeast. My other thought is that perhaps the yeast needs a little nutrient to help it along.
If you started with a Sg of 1.100.. that is a very high finished alcohol level if you finish it dry. You could drink it as it is, or you could make a yeast starter and gradually feed your wine to it, to get the wine fermentation restarted.
I think if you fermented this out to completely dry, you'd have an alcohol taste and lose the plum flavour, a good starting SG for a fruit wine is between 1.080 and 1.090.
Allie