A few months after their victory, Katniss Everdeen and Peeta Mellark are about to embark on their Victory Tour. Katniss is not happy with all the changes in her life, her relationship with Gale Hawthorne has changed, as has her way of life.

President Snow visits Katniss and orders her to convince him and the country she is in love with Peeta or he will kill Gale. This order is given due to the unrest in the districts of Panem since her defiance, during the Games. She tells Haymitch about the threat and he explains the only way to keep everyone safe is for her and Peeta to marry.

Katniss and Peeta visit Rue and Thresh's district and make statements of support to the late tributes' families. The returned support of the crowd is met with executions by Peacekeepers.

Peeta at the end of the tour proposes to Katniss, but it is not enough to satisfy President Snow. Katniss finds out District 8 is in rebellion and in reaction asks Gale and Peeta if they will run away with her. They both say yes, but have their reservations.

Then a shocking event happens, when Gale is whipped for poaching and Katniss throws herself in front of him to stop the punishment. Katniss realizes instead of running away, she needs to stay and start a rebellion in District 12. But the new Head Peacekeeper has fortified District 12 and threatened the citizens, so she gives up the idea of rebellion.

One day she slips into the woods to visit her pond and she is met by a Peacekeeper, who shows her a cracker with the image of a mockingbird on it, similar to the watch the Head Gamesmaker showed her. The Peacekeeper is actually an escapee from District 8. The escapee and her companion are trying to reach the destroyed District 13, because they think people are living there.

Days later Katniss watches a television special which features her wedding dress photo shoot and reveals who will be participating in the Quarter Quell, which is held every twenty-five years. It is past victors who are to serve as tributes, meaning Katniss is going back into the arena. She and Haymitch determine that they will ensure Peeta's survival during the Quell.

On the train ride to the Capitol, Katniss and Peeta become close again. Peeta helps Katniss deal with her feelings of leaving her family and Gale behind without saying good-bye.

Peeta watches tapes of the victors they will be competing against. Katniss wants to see the tape of Haymitch's victory. They find out he discovered a force field the Gamemakers used to keep the tributes in the arena. Haymitch used the power of the force field to help him win. Knowing Haymitch is cunning and also made the Gamemakers look like fools, allows Katniss to look upon him with new confidence.

At the Training Center Haymitch tells Katniss and Peeta, they need to convince everyone they are still in love and to make friends with the other competitors. He declares they need an alliance to survive the Games.

Katniss finds friends in the victors from District 3 and Mags from District 4, but she and Peeta decide to not to form an alliance with anyone.

During the televised interviews two things happen; Katniss' dress turns from a wedding dress into a dress resembling a mockingjay and Peeta lies, telling the audience he and Katniss are married and expecting a child.

The Games are held in an arena which has land strips separated by water. When Katniss and Finnick Odair, from District 4, reach the Cornucopia, he shows her a bangle signaling he is on her side. Together they, Peeta, and Mags, an old woman from District 4, form an alliance.

In the jungle, Katniss discovers a force field, but she is too late to warn Peeta, who is knocked unconscious by it.

Later, a poisonous fog envelops them causing blisters and damage to their nervous systems. They flee the area, but Finnick cannot carry both Peeta and Mags, so Mags sacrifices herself in the fog.

They camp out on the beach and are joined by Beetee, Wiress, and Johanna. Wiress is key to Katniss figuring out the arena is a large clock, with the attacks coming at specific times to specific sections.

While at the Cornucopia to test the clock theory, the group is attacked and Wiress is killed. The rest of the alliance suffers through various attacks orchestrated by the Gamemakers. It is during this time Katniss and Peeta realize Haymitch has lied to them, by telling each that they must sacrifice themselves to save the other.

Beetee comes up with a plan to eliminate two of the tributes. He has a wire which will electrify the beach and kill anyone on the beach. The plan works well, until the wire is cut while Katniss and Johanna are running it to the beach. Johanna attacks Katniss, which makes Katniss think everyone has turned on her and Peeta. As she tries to rescue Peeta, she realizes the true enemy is the Capitol. To rebel against the Capitol, she wraps Beetee's wire around an arrow and shoots it through a chink in the force field causing an explosion.

She is extracted by Haymitch, who tells her she is being taken to District 13. The alliance was a plan to save her, but, unfortunately, Peeta has been captured by the Capitol and District 12 has been destroyed. Haymitch explains she needed to be saved because she is the mockingjay, the lifeblood of the revolution.

Katniss and Peeta must endure being put into the arena again, but this time they have help. Haymitch and others have orchestrated a plan to save Katniss, because she is the symbol of the revolution. Katniss shows once again she is willing to do whatever it takes, to try to save those she loves from danger.