Question about plagiarism

I have a little bit of a dilemma and am in need of help from someone out there! That's where you readers come in =]

Right.

Like any one else, I know what plagiarism is. It's taking someone elses work and claiming it to be your own. Bad thing.

Now, what I'm asking about is this:

I have a new fic I'd like to post. It's very heavily based on Silent Hill 2, like, basically the same plotline but with different characters and some places are renamed.

If I were to post that, would it count as plagiarism? Even if I posted a disclaimer?

Thanks, guys,

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