In most stories, your protagonist wants something—to change a law or the government itself, to avenge a death, to hook up with the cutie, to dispel a curse—and your antagonist usually wants something that is in direct opposition of whatever the protagonist wants.
From those opposing wants come the narrative conflict and thus plot.
"Exposition" can be a scary word. In some writing circles, "experts" will warn you to exercise extreme caution when using it, or they'll make it out to be a difficult but necessary evil. But ultimately, exposition is just another writing tool, and it's used in all sorts of writing, even beyond fiction. Think of it this way: no matter what you're writing, you want your readers to understand and follow your train of thought.