Wow. Very well written, I loved reading it, I was hoping u would write an ending I had in mind. ( Though I hope it never ends lol)
Hurt penny and kill her so that the adults feel as much pain as she does. Even though you keep mentioning that they don't want to hurt her, it really sets off the rythm of the story, (acc to me, please don't see this as a hate comment I'm just saying how I read it) and make someone really want to hurt penny, and kill her off in the end.
I would love to read whatever ending you give to the story, after all its yours, but this one just feels fitting to me. Thanks for writing! Good job!