After Katniss shoots Coin instead of Snow, Snow laughs and coughs himself to death as the crowd erupts. Peeta stops Katniss from biting the nightlock pill hidden in her sleeve, so she is arrested rather than allowed to die. The guards return her to her old room in the Training Centre, where she is bruised, isolated, and watched. Because she expects torture and execution, Katniss immediately begins planning suicide, but surveillance and morphling withdrawal repeatedly defeat her attempts.

As days stretch into weeks, Katniss swings between self-starvation, dependence on the pills, and numb waiting. She sings the songs her father taught her, watches the snow, and grows afraid that the new regime may keep her alive only to use her again. That fear hardens her resolve to refuse any future role. Instead of an execution order, however, Haymitch arrives and tells her that her trial is over and she is being sent back to District 12.

On the flight home, Plutarch explains the political aftermath. Coin's death created chaos, Snow also died, and an emergency election made Paylor president. Katniss was exonerated largely because Dr Aurelius testified that she was mentally shattered, although she must remain under his care by phone and stay confined in District 12. Back in Victor's Village, Haymitch reveals that Katniss's mother has chosen to remain in District 4, so Katniss returns to an empty house where Greasy Sae quietly keeps her fed while she sits with grief, ignores calls, and delays deciding whether to live.

Katniss slowly begins moving through the house again, finds saved family objects and her old bows, and learns that Gale has taken a job in District 2. Her reaction is relief, which confirms that their bond is over. When she ventures outside, she sees crews recovering bodies and a mass grave for District 12, then collapses from weakness. Soon after, Buttercup returns from District 13 looking for Prim. Katniss's rage at the cat breaks into her first full release of grief, and after caring for Buttercup she finally calls her mother and mourns with her.

Peeta, delayed in the Capitol by Dr Aurelius, returns as well and plants evening primroses for Prim. Following Dr Aurelius's advice, Katniss proposes a memorial book modeled on her family's plant book, and she, Peeta, and later Haymitch fill it with names, images, and precious details of the dead so they will not be forgotten. As District 12 slowly rebuilds around farming and a future medicine factory, Katniss hunts, Peeta bakes, and they help each other endure flashbacks and nightmares. Their companionship deepens into love, and when Peeta asks if Katniss's love is real, she answers that it is.