That's a never ending discussion among dramatists. My teacher, Robert McKee, used to say that plot and character are the same. Certain things happen only to certain people. For John Truby the plot is a lesson for the protagonist that teaches him or her how to overcome his/her character flaws, therefore he also regards plot as secondary to character. On the other hand, an interesting character may be enough for a great novel, but not good enough for a dramatic play. I agree with Frank Capra who said: "The whole thing is you've got to make them care about somebody." You do if that somebody is someone you like and if he or her is threatened. Conflict is as important as character. Without conflict there is no drama. More important: Without conflict character does not show. True, without character there's no story. But without story your character remains lifeless. How someone acts under pressure reveals who he is. As a dramatist you have to invent revealing situations. Character and plot are far from being the same. They are connected, though, like everything in a well structured story should be.