I want to start a Game of Thrones (d20) campaign. My idea is based on the first book of seven (which comprises the whole story).

I don't want to change the course of the novel, but if my PCs are somewhat important to the main plot they might change it.

I can't give them the main characters to play, because as PCs they don't have to follow a pre-written plot, but neither do I want them to feel like nothing they do matters.

What to do then? Should I let the plot deviate according to the PCs' actions, or should I make the PCs' thread unrelated and use the plot as background to the PCs' actions?

**Is it better to allow the course of the novel to change during play, or to start the PCs on a different course?**