Ok, so this movie is about aliens that take over the minds of human bodies. This movie is about the "soul" (alien) Wanderer. Wanderer was put inside Melanie Stryder's body in order to find the last humans surviving, so they can invade the bodies of those bodies too.
When a soul is inserted into a body, the human that was on earth before should fade away and let the soul control his/her body forever. However, Melanie is very strong and protective of her family, so she refuses to go away and instead, becomes stronger and stronger rather than the other way around.
Melanie leads Wanderer to a desert for a few days, just to make sure that if she really brought Wanderer to her family, it wouldn't cause her family any danger.
Uncle Jeb, Melanie's favorite uncle, finds them in the desert. He still treats Wanderer like she's still Melanie because he still thinks that it's his niece's body, though she's not human anymore.
Uncle Jeb lives in a cave in the desert with all the other human survivors that he knows. He brings Wanderer to the cave.
Once all the other people know that one of their enemies are living with them, they are very angry and many of them even hate Wanderer. Not for her personality though, but because she's a soul.
Once Jamie (Melanie's brother) and Uncle Jeb know that Melanie is still alive and well inside of Wanderer, they begin to like and protect her.
This movie was originally an 800 page novel by Stephanie Meyer, author of the Twilight Series. I'm reading the book now, so I was thinking maybe you should try it out as well! For those of you out there who have watched the movie, read the book, or even both, please comment what you think about it! I would be delighted to hear your thoughts!