Winning the game didn’t mean that it’s the end of their role because it turned out that they haven’t even started yet. When they were declared victors, Peeta and Katniss faced more consequences. When Katniss and her family moved to the victor’s village, they were visited by President Snow, telling her that she caused a rebellion. She made the capitol look like a fool when she outsmarted them using the berries. As a consequence, she ought to prove that she’s really inlove with Peeta, that what she did was simply because she was blinded by love and she never intended to start a rebellion. She ended up being engaged to Peeta.
It was later announced that there was a Quarter Quell. Thr president made the game different, and more exciting since it will be the 75th Hunger Games. The victors from each district are going to the arena to compete. Together with the other victors, Peeta and Katniss went inside the arena once again. The arena was revealed — it was shaped like a clock with deadly challenges in it. It was like the players are playing against the arena, and not against each other.
Haymitch and Katniss agreed on keeping Peeta alive no matter what. Later on thry formed an ally consisting the 2 of them, Finnick, Mags, Beclee (?) and Johanna. Katniss’ plan on keeping Peeta alive didn’t go accordingly because their other allies had their own plans which was better plotted. In the end, Johanna took the tracker from Katniss’ arm. Believing that she’s been betrayed and that Peeta is already dead, she shot bomb which blew arena. After that, she was rescued by some hovercraft — and all of it was Haymitch’s plan.