Stephen King thinks that plot is
The good writer’s last resort and the dullard’s first choice. The story that results from it is apt to feel artificial and laboured.
I lean more heavily on intuition, and have been able to do that because my books tend to be based on situation rather than story. Some of the ideas which have produced those books are more complex than others, but the majority start out with the stark simplicity of a department store window or a waxwork tableau. I want to put a group of characters (perhaps a pair; perhaps even just one) in some sort of predicament and watch them try to work themselves free. My job isn’t to help them work their way free, or manipulate them to safety […] but to watch what happens and then write it down.
I haven’t read any of his novels, but I think that Stephen King is probably a very good writer (despite his popularity). I don’t think what he says here applies to screenwriting, but it provides a guide to an alternative way of finding your story: trust your intuition.