STAR WARS THEORY (SPOILERS AHEAD)
(This post contains mad SPOILERS)
Okay, maybe Rey IS Luke's daughter (plenty of speculation about that already), and had been training with him and the other young Jedis, without being told that Luke was actually her father (to avoid either perceived favouritism or her getting too attached to him or something else Jedi-like. They have a weird sense of ethics and weird hang-ups about parental attachment). And what if Kylo Ren was supposed to kill her with all the others, but he couldn't, for whatever reason? Maybe he loved her, or maybe she was too strong with the Force even then. So he traded on her trust in him as her cousin, and brought her to Jaku and left her there, and told her that he or her parents would come to get her, and he told Snook (sp?) that he'd killed her. And then, maybe Rey figures it out in the next movie before Luke realizes who she is, and they'll all be fighting Kylo Ren, and Luke will yell, "You killed my daughter!" AND REY WILL SAY, "NO I AM YOUR DAUGHTER."
