and a rouge psychopathic killer in their mix

I think the phrase you're looking for is "in their midst"

Also, that description is a gigantic run-on sentence. That's a comma splice after "mix," it would be better to make that a period. Really, the whole thing would read better as:

Spike and Echo find themselves in a town within the Everfree with unidentified changelings and a rouge psychopathic killer in their midst, and every day somepony dies. Can our protagonists defeat the forces of evil and save the day? Does it really matter in the end?

Read and find out for yourself... 

Takes place a few years after the events of Alone in the dark

Sorry! I don't mean to be nitpicky or anything, but I know how much readers can be put off by grammar mistakes in a story's description. This is one part of your story you really want to be sure is error-free.

8473885
Thanks I will fix the issues asap