Okay, let's try this over here now

Hey, I was wondering if anyone had time to read what I have so far of a Big Bang story that's Supernatural/Miracles but doesn't take place in any other universe I've created? The basic premise is that Castiel sends Sam back in time to save the life of Paul's mother, Theresa. Currently, the story's at around 25,000 words. (It's going to be a monster when I'm finished with it.) I don't really need a full beta at this point - what I want is for someone who hasn't read all the notes to tell me if they can figure out what the heck's going on. (The two betas who have been reading it so far have also read the notes.) There are clues all through these six chapters I've written. What is Castiel lying about?

I need someone who won't be afraid to possibly be wrong. If you're right, I'll tell you, but if you're afraid to venture a guess on this, I can't use you. If you're going to be like, "I know what's going on BUT I'M NOT TELLING YOOOOOU," I can't use you. I'd also like it to be someone I kind of know instead of a name on my friend's list where I have no idea who you are.

Warning: There is some graphic het sex in this.

Any takers? I'm dying to know if my diversions have been successful so far, or if it's like super obvious.