Am I copying the Count of Monte Cristo's plot?

I think the plot sounds remarkably similar, but I don't think you need to worry about copying Dumas' masterpiece. Every plot device (including all the ones you have described) have been reused in some shape or form thousands of times. I once had a creative writing teacher tell me that there are perhaps 5 or 6 basic plot lines and every single piece ever written can be fit into those plot lines. The only thing is that there are thousands and thousands of permutations of those plot lines--especially if you interlace them. The key to being a creative writer is to put your own spin and perspective on those permutations. As it is, your plot seems interesting, just be careful that it doesn't become predictable or cliched. The key here is not to replicate Dumas' story, but to write your own.  more