Keep Up The Creativity!
Congratulations on writing and then sharing with the world! That's one of the hardest parts - putting the words on the paper themselves, so pat yourself on the back for getting to that point!
Read the story now
Here's some honest and unbiased feedback: your plot seems like it's going to be very interesting, but it looks like you could really work on sentence structure, paragraph breaks, and general mechanics of writing. Now, I don't claim to be an expert in any sense of the word, especially in mystery/horror/thriller, but I think this is true for all stories. Your summary gives away a lot, and it's all one sentence! The summary, or synopsis, should really just be a way to intrigue your reader, give a small example of your writing voice (if possible), and get them wanting to know what's going to happen. If it were me, I'd make it a few sentences, vary the structure a little, and maybe just introduce us to what the very beginning might be - don't write the whole story in the summary!
Keep in mind that you can ignore me, or listen - it's a free world, and you don't have to anything strangers on the internet tell you do (rather, it's probably good idea NOT to listen to strangers on the internet)... BUT! I have some quick advice to improve your story.
Paragraph breaks are your friend! A long paragraph can turn off a reader so fast - all those words put together are scary! So add a line break whenever the 'camera' moves, you introduce a new idea, or dialogue from a new person starts. This will help retain readers! (I see that you use some breaks later in your chapter, but you could still use more at strategic points).
I would also work on varying your sentence structure and trying to avoid run-on sentences. Add a comma or two (where they're supposed to go, of course) and don't be afraid of semicolons! All of the punctuation marks - they're your friends! And of course, if you want to break the grammar rules a little, for the sake of your art, then do it. Writing is art, after all.
Another thing, and more of a wording critique, is to try not to spill too many details into the very beginning. It's overwhelming! Show us what your character is doing, feeling, or thinking, if you like, but you may not necessarily need to tell us some specific details that simply aren't relevant at the time. But I could be wrong - maybe these details are more important later in the story, and I was supposed to pay attention to them. If that's the case, point them out, but make sure it doesn't distract from the actions of the story.
All in all, I am so proud of you to be able to create something from nothing. It is no small feat, to build a story! Then, you even got to write it down, and then had the courage to post it online! I know a lot of people, myself included, who struggle with sharing their work. You are amazing! Keep up the creativity, and keep up the drive! I would be honored to see you grow as a writer, and if you'll allow me, I would love to read more work from yours and help you to become a better writer. That's all life is, is learning and growing. Let's do it together!
Remember, a first draft is just there to make a story exist! It isn't bad, or good - it's just a baby. It needs care, love, and patient effort. The second draft is to make it functional, and the third is to make it effective. The way to get better is to keep going! You've started your journey, so keep putting those feet in front of the other, and travel on.