Often, when I read the conclusions on Finish the Story, I have a sense that more is in the author's mind. That's what I feel here. If it weren't for the 500 word limit, I think you would have rounded this more fully. It's a complex scheme you've got worked out, with the different tribes, the history of the mother, Shiro on the run...always it seems on the run.
This is like a tantalizing piece of a story...well written but leaves us wanting to know more.