Why is freewill basically a joke?
Modern neuroscience is actually demonstrating that the notion of free will may actually be somewhat of an illusion.
With regards to scripture, what is interesting is that god is actually undermining the whole notion of free will. He indicated he provided a sense of autonomy to his creation but at the same time gave instructions for how they should behave. That in and of itself indicates that free will, as denoted by the Bible is also not truly 'free'.
One thing to note is the whole concept of 'god's plan'. If one ascribes to that notion, that brings up your movie analogy. I also like to use the concept of a video game.
As a player of the game, it appears as though my character has 'free will'. I have (mostly) freedom of movement and can adjust tactics accordingly to achieve an objective. But ultimately, I am beholden to the script; i.e. the plan. As such, I can never truly experience free will since I am actually a slave to the programming of the game. The same is true in the case of 'god's plan'.
"Our future lies not in our dogmatic past, but in our enlightened present"