There are just a few grammatical mistakes, mispellings and things like that. When two different people are speaking in the same paragraph, you ought to space it apart into two paragraphs. Just little minor things, but overall, the story was great.

I really, really like your story, but there are a few constructive comments that i would like to make, hopefully improving it further.

One, in your first sentence when it says "the same way it did many times before" 'had done' would probably sound better than it did. Also in your first sentence i think you should end it after 'before', so that it reads "Fog rolled through the city of Clifton, NJ, like it had done so many times before. But this fog was different. It was darker, denser, more mystifying than it had ever been ever been before on October 31st.

Two, in your third paragraph you should have said "his mom immediately asking him for every detail of his plans for the evening", and maybe made "later was not good enough answer for her." a sentence of it's own.

The last bit of constructive criticism i wished to give you was that whenever a new person starts speaking, you should start a new line, because in some places you have whole paragraphs of conversationa and it gets a bit confusing.

But don't take this the wrong way. Your story is really good. You have a lot of description in it, and have created a really suspensful story. The end was particularly good.