Katniss ends up not being able to speak temporarily because of what Peeta did to her. She’s required to wear a special collar and is asked to lie still. Prim stays by her older sister’s side to make sure that she’s going to be fine. Plutarch, Haymitch, and Beetee join the two of them to explain what happened to Peeta. Beetee and Plutarch explain that Peeta has been “hijacked”: injected with tracker jacker poison to trigger an increased feeling of fear and paranoia. It’s a mental torture designed to break Peeta and make him forget about his feelings for Katniss and make him want to kill her. They admit that they’re unsure if they can still bring back to old Peeta, as the effects might be irreversible. Plutarch tells Katniss that Snow and the Capitol have already done measures to retaliate. Portia, Peeta’s stylist from the games, has already been killed.
Katniss returns back to her quarters with her sister. Once Prim leaves, she finds herself being asked to go back to Special Defense to meet up with Gale and Beetee. They show her the new weapons developed for the war. Katniss feels as if these weapons are inhumane. Haymitch arrives and tells Katniss that medics are going to try a new technique to bring back the old Peeta: by bringing in a neutral acquaintance of the two of them from District 12 to trigger memories other than fear. This acquaintance is a friendly girl named Delly. Katniss thinks that Peeta won’t be able to associate Delly with her. Katniss, Haymitch, and Plutarch watch from a one-sided window as Delly enters the room where Peeta is tied to a bed. Delly finds it difficult to talk to Peeta. Suddenly, he remembers all about the destruction of District 12 and start blaming Katniss for it. He calls her a mutt (a genetic creation that has the voice of a human but the appearance of a terrifying animal) Katniss gets upset by this, as she thinks that Peeta no longer sees her as a person. She demands the rebels to give her something war-like to do to distract herself from this. Plutarch tells her that she can be assigned to District 2.
Due to Katniss stubbornness, she is sent to District 2, where the situation is extremely dangerous.
Katniss describes what District 2 looks like. It’s located at the center of a mountain that’s called The Nut by the rebels. It’s a place where the Capitol stores their supplies, as well as where they get some of their armed forces. The Nut is hidden, difficult to attack and very easy to defend, hence the Capitol’s interest in it. Katniss focuses on fighting to keep her mind off of Peeta. Plutarch tells her that Peeta is improving, something that Haymitch contradicts. Reinforcements are sent to District 2 to help out. Gale and Beetee arrive as well. Gale and Katniss find themselves alone and started talking about their relationship: about how Gale thinks it’s unfair for Katniss to be torn between the two of them. They kiss and Gale stops the moment—saying that Katniss isn’t stable enough to make a decision right now.
The next day, they start creating a new plan to attack The Nut. Katniss realizes that the District 2 commander, Lyme, is a former winner of the Games. Gale suggests a plan to attack The Nut: create an avalanche to keep everyone inside from escaping.
Katniss starts to notice the vengeance living within Gale and thinks if she could still recognize him or not.
Gale’s suggestion received mix reactions from the others. The people of District 2 are innocent. Katniss realizes that Gale is potentially dangerous because of his sacrificial tendencies. Boggs suggested a compromise in which they still use Gale’s plan, but they have to take the survivors as prisoners of war instead. Katniss takes part with the attack on The Nut as the Mockingjay. Their plan works and the avalanche traps everyone inside. Katniss has a flashback of when her father got trapped during the mining accident. Haymitch makes her snap out of it by screaming to her via her earpiece. She goes inside and feels relieved when Boggs told her that they went with the prisoner of war tactic. Any survivors will be taken to the train station, where other rebels are waiting.
Haymitch informs Katniss that Peeta remembered an encounter with Katniss’ father singing “The Hanging Tree”, the same song she sang for a propos. Haymitch tells Katniss to act as a Mockingjay and recite a speech encouraging the survivors to turn themselves in instead. Just as she was about to start, survivors started coming out. She tells the rebels to stop from attacking, with her running out to defend a survivor. She tells the rebel that they’ve all suffered in the same way and were used by other people for their personal gain. She commands the rebel to kill her, as it was what the Capitol would have wanted. She encourages everyone to join together and not fight each other, but rather together against the Capitol—until she gets shot.
Katniss’ hard headedness put people into danger once again. This time, causing more innocent lives to be killed.