The moral is that you should stand up for what you believe in no matter what your circumstances are.
Katniss is powerless. She lives in a dystopian society where her district, District 12, is on the lowest rung of the power ladder. In her very poor district, she is the poorest of the poor. Her father died when she was younger and her mother never recovered, which leaves Katniss as the family’s main breadwinner. She has to take care of herself, her mother, and her little sister, Prim.
Katniss takes care of her family mostly through illegal means. She hunts and trades on the black market. Living in a totalitarian society, she learned from an early age that you do what you can to get by, even if that means breaking laws. One of the worst abuses of her government is The Hunger Games. Children from the poorer districts compete to the death for the entertainment of the better off Capital.
Since Katniss is poor, she has had to sell herself for more shares in the Reaping, increasing her chances of being chosen for The Hunger Games. Her little sister is entered too. When her sister’s name is chosen, she knows that she would never make it. Katniss volunteers to take her place.
“I volunteer!” I gasp. “I volunteer as tribute!”
There’s some confusion on the stage. District 12 hasn’t had a volunteer in decades and the protocol has become rusty. The rule is that once a tribute’s name has been pulled from the ball, another … can step forward to take his or her place. (Ch. 2)
Katniss volunteers because it is the right thing to do. She has always protected her sister. In volunteering for The Hunger Games, she is just protecting her again. She realizes that she is most likely going to die. Only one person from her district has ever survived. Yet she volunteers, because in doing so she is saving her sister, at least this once.
During the game, Katniss does her best to maintain her own personal code of ethics. She plays the game, but mostly evades. At the end, she uses a combination of intelligence and guts to save someone else—her partner Peeta. She also saves herself, although what she does is very dangerous.
Katniss is relieved to learn that there can be two winners from the same district, but when she and Peeta are the only ones left the rule is rescinded. Refusing to kill Peeta herself, Katniss arranges for them both to take poisonous berries. She knows that the Capital won’t want to lose both of its victors. It works.
The frantic voice of Claudius Templesmith shouts above them. “Stop! Stop! Ladies and gentlemen, I am pleased to present the victors of the Seventy-fourth Hunger Games, Katniss Everdeen and Peeta Mellark! I give you — the tributes of District Twelve!” (Ch. 25)
This is dangerous because the powers that be will realize they were manipulated and she will get in trouble. She does it anyway, because she has no other option. She is in a situation where it is either kill Peeta or kill herself, and she refuses to kill Peeta. She took a calculated risk with the berries.
Katniss's insistence on doing the right thing makes her an inspiration to the downtrodden people of Panem. She becomes the Mockingjay, the symbol of the rebellion. People all over the country start to stand up for what they believe in, following her example.