Katniss believes that Coin must really want her dead. Boggs, the unit leader, promises to keep Peeta contained but does confide in Katniss that Coin probably does see Katniss as a threat. Coin wants to remain in power after the revolution, and if Katniss isn’t going to support Coin’s leadership, then Coin will use her in whatever way she can to give the rebellion momentum. For now, that might mean turning Katniss into a martyr. For everyone’s safety, the crew sets up an around-the-clock guard on Peeta.
Katniss struggles between her desire to kill Snow and her inability to save Peeta from his own mind. Peeta is able to control himself but is still skeptical of Katniss. The team develops a game for Peeta called “Real or Not Real,” in which Peeta describes memories and squad members tell him if those memories are real or fake. It’s a slow, excruciating process for Katniss, but she can see that there is some of Peeta still left, and this gives her hope.
To get some more exciting footage, the squad embarks on a staged mission to a residential block to set off some pods. While filming, the crew adds smoke to enhance the shots and has each individual reenact his or her response to the pods going off. Just as everyone is laughing and teasing one another about their acting jobs, Boggs trips a bomb and his legs are blown off.
Immediately the unit is thrown into a true battle with another pod, a toxic black oily substance coming after them. Peeta loses control and attacks Katniss. The others contain him, and they seek shelter in an apartment. Before he dies, Boggs tells Katniss to continue on her mission, not to go back, and to kill Peeta.
The Capitol televises a broadcast declaring Katniss and her unit dead. Katniss knows they must advance as quickly as they can before it’s discovered that they survived. Peeta asks that they kill him because he knows that he’s a danger to the unit. Katniss hopes that she’s not keeping him alive to use in her own “Games,” one in which she refuses to let Snow win. Katniss knows that, more than anything, Snow would love to make Katniss kill Peeta. Still, she refuses to do this.
The unit decides that their clearest path to the Capitol’s center is underground. Led by Pollux, who spent five years as a slave to the Capitol in the sewers, the group settles in a room for the night. While Katniss stands guard, she talks to Peeta about his memories. Earlier, he’d said that the fake ones seemed shiny to him. Katniss thinks this is encouraging, that he can at least sort out the real from the unreal. For the first time since the Quarter Quell arena, Katniss touches Peeta voluntarily, brushing the hair across his forehead. Though he’s tense, Peeta lets her do this and soon relaxes, understanding that Katniss really is trying to protect him.
They awake the next morning to a hissing sound. Katniss recognizes that it’s her name being spoken. The Capitol knows they survived and has sent mutts, four-legged, white, reptilian-looking beasts that drive themselves mad with their hunger for Katniss’ blood, killing everyone who gets in their way, after them. With the hissing comes the smell of roses, another message from Snow. It’s a mad dash through the tunnels and up ladders, with some team members getting eaten or killed by pods. Katniss sees the mutts. The smell of roses is nauseating to Katniss, paralyzing her with fear. Just as Katniss has climbed out of a tunnel, she watches as the mutts tear at Finnick, killing him. She gives the self-destruct code to the Holo, a handheld device that displays a holograph of the Capitol and the pods, and tosses it below, killing the mutts and blocking the tunnel.
All that remain are Gale, Cressida, Pollux, Peeta, and Katniss. They disguise themselves and join the throng of Capitol citizens outside, all of them moving about in chaos as their streets are evacuated. Cressida leads them to a fur shop owned by a woman named Tigris. Tigris used to be a stylist in the Games before Snow deemed her surgically altered feline face too grotesque. Tigris shelters Katniss’ team in a hidden cellar.
While there, the group recuperates, and Tigris brings them news of developments in the Capitol, saying that the rebels are advancing. Katniss knows they need to leave soon, as shopkeepers are being asked to house Capitol citizens whose homes are on occupied streets. Katniss wants Peeta to remain behind with Tigris, hoping that he’ll be safer there than out in all the chaos. Peeta decides, though, that he will go out on his own to act as a diversion in case Katniss and the others need it. Gale gives Peeta his nightlock pill in case Peeta’s captured.
They leave early in the morning, bundled up and styled by Tigris. Cressida and Pollux go first, leading the way to the City Circle. Katniss hugs Peeta goodbye, and she and Gale leave as well. It’s as if Katniss and Gale are once again hunting partners, the only people in the world that matter. Suddenly, there’s an outburst of rebel fire, hitting citizens in the streets. Chaos breaks out as Katniss and Gale scramble and take the guns of dead Peacekeepers. They continue making their way toward Snow’s mansion, shooting reflexively and protecting one another. Without warning, the ground below them begins to tilt, folding in like flaps over a deep abyss. Katniss leaps and is able to grab hold of the street and pull herself to safety. Gale is captured by Peacekeepers.
Nearly broken by grief, Katniss presses on to the City Circle, knowing that the only way to save Gale is to kill Snow and end the war. When Katniss arrives outside the president’s mansion, she sees that he’s made a human barricade of children around his home. A hovercraft marked with the Capitol’s seal flies overhead and drops small parachutes. The children reach out for them eagerly, opening them up. Just then, the parachutes detonate. Rebel medics rush to the scene, dashing for the children. Katniss catches sight of Prim and starts running after her, trying to keep her from harm. Prim looks up and sees Katniss. Prim starts to say Katniss’ name when another round of bombs goes off, killing Prim and severely injuring Katniss.
Katniss becomes the literal “girl on fire.” She enters a dreamlike state in which she is in horrible pain and wants to die. Above her is sky with those she loves as birds, yet her wings fail her and she plummets into seawater where creatures claw at her. Steadily she comes back to life but remains in a hazy realm in which her visitors are both alive and dead. The doctors graft new skin to her body. She improves physically but is buried in grief. She learns that Peeta survived and is in the burn unit. Gale also survived and is in District 2 cleaning up Peacekeepers. Cressida and Pollux made it out alive, too.
The Capitol falls, and President Coin now leads Panem; Snow is being held prisoner. The one thought that drives Katniss on is that she still gets to kill Snow, but she knows she’ll be completely empty once that is done. Released from the hospital, Katniss lives with her mother in a room in Snow’s mansion. She wanders during the day and eventually stumbles upon Snow’s greenhouse where he grew his roses. She enters, wanting to clip a white rose to place over his heart before she shoots him. Just as she’s clipping the rose, she hears Snow’s voice. He’s being held prisoner here, shackled. Snow tells Katniss that he wasn’t the one responsible for the bombs that killed the children and Katniss’ sister. He claims that it was a part of Coin’s plan all along, another way to ensure that Coin defeated the Capitol and could move into power. Coin, Snow says, played both him and Katniss for fools. Katniss tells Snow she doesn’t believe him, but privately she’s not so sure. Coin has done everything Snow set out to do.
Just before Snow is scheduled to be executed, Coin calls a meeting of all the remaining victors to vote as to whether or not they should hold one last Hunger Games. The children of the most powerful Capitol citizens would be tributes, and it would serve as punishment for all of the Capitol’s wrongdoings in the past. Peeta, appalled at the suggestion, votes no. Katniss, in the end, votes yes for Prim. The total vote is in favor of the Games, and Katniss sees that after all that death and suffering, nothing has changed.
The City Circle is filled with a roaring crowd, ready to see Snow die. When Katniss takes her place and faces Snow with her bow and arrow, ready to execute him, she searches his eyes for signs of remorse or anger or fear. All she sees is amusement. Then she remembers their earlier agreement, that they promised not to lie to each other, and she shoots Coin with her arrow instead, killing the new president of Panem.
Katniss is quickly taken to her old Training Center room where she waits for a death sentence. Weeks pass, during which she sees no one. She wants to die and tries to starve herself. She begins to sing for hours on end. She can’t understand what’s taking so long. Finally, Haymitch enters her room and tells her they are going home.
As they head back to District 12, Plutarch describes how Snow was killed in the chaos that followed Coin’s assassination. Commander Paylor has been voted in as president. Katniss learns about her trial and how Dr. Aurelius, Katniss’ “head doctor,” came to her aid by stating that she is highly disturbed and shell-shocked, so they are sending Katniss back to District 12 where Haymitch will watch over her.
Katniss spends months alone in her house, neither showering nor changing her clothes. She mourns for Prim and becomes an empty vessel of despair. Greasy Sae comes to cook for Katniss. Katniss has lost all will to live. Spring arrives and Greasy Sae encourages Katniss to go outside, maybe do some hunting. Peeta comes and plants primroses around the house. Katniss showers and her old, dead skin comes off her in flakes. She throws Snow’s rose in the fire, as well as her old clothes. She rids her house of his smell. Slowly, she comes back to life. She starts a book, collecting memories of all those who died. Peeta and Haymitch both make contributions to the book. Eventually the rate of entries slows. Katniss hunts. Peeta bakes. They grow back together, and Katniss knows this is right. She would have chosen Peeta all along. While Gale possesses the same intense fire that Katniss has, she needs someone who sees hope in the future, someone who makes her believe that the world will be good again: Peeta.