Need Some Help

So I've got like 3 story ideas, the only problem isn't that I can't write them but that I can't write their descriptions. They easily describe the first one or two chapters, but after that they don't hold up. Characters and themes are introduced that aren't even hinted at in the descriptions, and I'm worrying that people who come won't like it and people who would like it won't because the descriptions are suggesting the wrong stories. For example, one is an Adventure/AU fic when the description makes it look like a Sad/AU fic. The first chapter is a bit sad when you think about it, sure, but that's an introduction to the later parts. So what do you all think? Any tips? Should I ditch stories that look like a mish-mash of genres? I'm open for ideas!
-Requiem