In Chapter 20 of The Hunger Games, Katniss, Peeta, and Haymitch are preparing for the final round of the Hunger Games. They are all feeling anxious and nervous, as they know that only one of them can come out alive.
As the final round begins, Katniss and Peeta are forced to fight against each other. Katniss is hesitant to attack Peeta, knowing that he is her ally and friend. However, she also knows that she must do whatever it takes to survive. Peeta, on the other hand, is more willing to fight and tries to attack Katniss.
As the fight continues, the other tributes start to drop out, one by one. Eventually, it comes down to just Katniss and Peeta. They both realize that they cannot kill each other, and they decide to refuse to fight and instead commit suicide by eating poisonous berries.
The Gamemakers, who are in charge of the Hunger Games, are not pleased with this outcome and try to force them to fight. However, the people of Panem, who have been watching the Hunger Games on television, start to revolt against the Gamemakers and the Capitol. The Capitol, realizing that they cannot control the situation, declares that both Katniss and Peeta are the winners of the Hunger Games.
In the end, Katniss and Peeta are able to survive the Hunger Games and return home to their families. However, the experience has left them both scarred and changed forever. They know that they will never be the same again, and they will always carry the memories of the Hunger Games with them.