So ... what do I need to know to understand it?
AFAICS, Summer Glau is Weird Girl Who Can Kill You again, but this time it is because of being a ROBOT FROM THE FUTURE rather than Ebil Gummint Experimentation. Like Arnie in the second film, she has been reprogrammed by the future resistance to protect John. (Presumably it is all set between the second and third films?) I imagine there is lots of exciting time travel paradox plotting that I will enjoy. From what I could see, the premise seemed to be that Sarah and John were hiding out but trying to