My screenwriting professor gave us a quotation from Henry James: "What is character but the determination of incident? What is incident but the illustration of character?" In other words, they both feed on and inform each other. Characters make decisions that alter or advance the plot, and the events of the plot change characters and inform their later decisions.

I've also heard that if you have a strong enough (sense of) character, all you need to do is drop them off in a premise and let them go, and the plot can pretty much write itself.

I can't really tie this into our context but I figured I might as well throw it out there. 'A'