You are succeeding in doing something that many writers of crossovers don't -- making the story understandable and enjoyable to someone who is only familiar with one of the shows. Other than knowing that Eureka is a science fiction show about a town where strange things happen, I know nothing of Eureka. I don't even have a clue as to what the strange things are, beyond that they are apparently related to aliens somehow. The only thing I didn't understand in your story was what "GD" stands for. I'm guessing it's something like "Government Defense," but I don't know. Fortunately, it wasn't necessary to understand its exact nature to comprehend the story's plot.
I hope this is proves to be the second in a long series of stories. Thanks for sharing.
Joy,
Lynn
