What is Katniss's role in advancing the plot of Catching Fire?
One distinct way in which Katniss advances the plot of Catching Fire is through her own internal understandings. Developmentally, she advances the plot in term of her commencing her victory tour. This is significant because it sets the stage for Katniss to begin the process in understanding how she feels about Gale and Peeta. At the same time, she no longer can claim a sense of ignorance about the political implications of her actions. Here, again, is an opportunity for Katniss to advance the plot. When she initially appeared in the Games, Katniss was more concerned about survival and sacrificing for her family. Now, President Snow makes her aware that there are political implications in her actions. If Katniss does not act in accordance to the Games' intent, solidifying the rule of the Capitol, her family will suffer. If she does at in accordance to the Games, then she has to accept the consequences of death as an almost foregone conclusion of the games.
Katniss develops the plot through her actions because so much depends on what she does. Unlike her previous times at the Games, Katniss is seen as a symbol. She can no longer do anything without others noticing it. She is seen as an object of both upholding the Status Quo and undermining it by the Capitol's leaders. Katniss is seen as a source of rebellion by the people who wish to break free of governmental control. She is seen as a competitor by others, but also with a source of envy for how she has captured the public's imagination. How Katniss depends on Peeta and seeks to remain independent of him is another instance of how what she does and what Katniss feels advances the plot in the narrative. To a great extent, it is Katniss's own actions in terms of sorting out how she feels about herself, the world, and her place in it that drives the plot of Catching Fire.