After winning the 74th Hunger Games in the previous novel, Katniss Everdeen and Peeta Mellark return home to District 12, the poorest sector in the country of Panem. On the day that Katniss and Peeta are to start a "Victory Tour" of the country, she is visited by President Snow, who explains that he is angry with her for breaking the rules at the end of the last Hunger Games, which permitted both Peeta and Katniss to win. Snow tells Katniss that when she defied the Capitol, she inspired rebellion in the districts.
The first stop on the Victory Tour is District 11, the home of Katniss's deceased friend and ally in the Hunger Games, Rue. During the ceremony, Katniss delivers a brief speech to the people of District 11, thanking them for their participants in the Games. When she is done, an old man whistles the tune that Katniss used in the arena to tell Rue that she was safe. The song acts as a signal and everyone salutes Katniss, using the same gesture that she used to say farewell to Rue. The old man and two other people are then shot, to Katniss' horror. Leaving District 11, Katniss and Peeta proceed to travel to all of the twelve districts and the Capitol. During an interview, Peeta proposes to Katniss publicly, hoping to settle the dispute between Katniss and President Snow and placate the growing rebellion. Despite this, Katniss learns that their attempts of subduing revolt in the districts have failed.
Shortly after returning to District 12, Katniss encounters two runaways from District 8. They explain their theory that District 13 was not wiped out by the Capitol, contrary to what the other districts have been led to believe, and that many of its residents survive in underground shelters. Later, it is announced that, for the 75th Hunger Games, 24 victors from previous years will be forced to compete once again. This is the third occurrence of the "Quarter Quell": an event that occurs every 25th year of the Games and allows the Capitol to introduce a twist. Knowing that she and Peeta will both be competing in the Games a second time, Katniss decides that she will devote herself to ensuring that Peeta becomes the Quarter Quell's victor. However, Peeta is devoted to protecting her.
During the Games, set in a jungle with a saltwater lake, Katniss and Peeta join up with two other previous victors: Finnick Odair, a 24-year-old man who survived the Games at the age of 14, and Mags, Finnick's 80-year-old mentor, both from District 4. After Mags's death, Katniss, Peeta and Finnick join forces with Johanna Mason, a sarcastic and often cruel victor from District 7, and Beetee and Wiress, an older couple from District 3 who are said to be "exceptionally smart". Wiress soon proves her genius by revealing to Katniss that the arena is arranged like a clock, with all of the arena's disasters occurring on a timed chart. After Wiress is killed, Katniss learns of Beetee's plan to harness lightning in order to electrocute Brutus and Enobaria, the two remaining Careers Tributes from District 2. In the final chapters, Katniss instead directs the lightning at the force field that contains the arena, thereby destroying the arena and resulting in her temporary paralysis.
When Katniss wakes up, she is being transported to District 13, joined by Finnick, Beetee, and her mentor, Haymitch Abernathy. She learns that Peeta, Enobaria, a District 2 tribute, and Johanna have been captured by the Capitol, and is informed that there had been a plan among half of the contestants to break out of the arena— Beetee had been attempting to destroy the force field in the same way that she did. The book ends when Katniss's best friend, Gale, comes to visit her and informs her that, though he got her family out in time, District 12 has been bombed and destroyed.