This idea sounds very interesting, despite the first chapter being a rehash of the opening scenes of Serenity. I understand that sometimes that's necessary to set the scene and introduce people to how the elements of the crossover are going to come together.
I am looking forward to more, but please, PLEASE, find it in your heart to spare your readers and write in past tense. It's SO much easier to read and it's often easier to write, because when fanfic authors write in anything else, they tend to make mistakes and constantly slip into past tense anyway. In fact, you already have.
Other than the tense shifts, there are some typos and spelling errors (like the following) that should be addressed.
-The Operative, even after having years of MENTAL and emotional training, is unnerved by HARRY'S silence and his vacant gaze.-
-With a sudden clarity of THOUGHT he understands what the boy wants.-
-You BETRAY/RELAY secrets to others, I will kill you.-