This was very good. Granted, I did have to read it twice, but on the second time through, I felt like I had a pretty good grasp on what was happening. Considering that I'm missing the context, that means you did very well describing the events. 

The only thing I would point out is that some of the sentences read a little weird, so maybe go through it and touch some of them up. An example would be the last sentence of the second paragraph. If you do that, I feel this would be a very solid prologue. Other than that, great job! I liked it. :)