The nation of Panem, which took over a post-apocalyptic America, is made up of the rich Capitol City and thirteen large surrounding districts, twelve of which are still inhabited and a thirteenth that was destroyed long ago by Capitol City during an attempted rebellion. Every year, as punishment for having triggered the rebellion years before, in each district a boy and girl aged between twelve and eighteen are chosen to participate in the Hunger Games, an event in which the participants (also called “tributes” ) must fight in a place called “arena”, which is controlled by Strategists by means of very sophisticated computers, as long as only one remains alive. The selection takes place through a ceremony called “reaping”, which consists in drawing a ticket from the many names of the candidates from an ampoule.
In District 12, the poorest of all the others, lives a girl named Katniss Everdeen (Jennifer Lawrence), very skilled in hunting and archery. Katniss spends most of the time in the woods with her best friend, Gale Hawthorne (Liam Hemsworth), looking for food to feed their families, who fell into misery after the death of the two fathers due to an explosion in a coal mine. During the draw for the 74th edition of the games, Effie Trinket (Elizabeth Banks), the person in charge sent by Capitol City to celebrate the harvest, draws Primrose Everdeen (Willow Shields), Katniss’s younger sister, but this one, just to save her life volunteers in her place.
Together with Katniss the baker’s son Peeta Mellark (Josh Hutcherson) is also chosen. This upsets Katniss, as Peeta had given her bread some time ago to feed herself in the period following the death of her father. In fact, with this gesture he had managed to give her hope to survive. Katniss and Peeta are then brought to Capitol City: each district has a team of coaches, with the function of preparing the “tributes”, both physically and psychologically, to participation in the games. Their mentor, Haymitch Abernathy (Woody Harrelson), the only winner of District 12, reveals what could save his life: the Sponsors, or the favor of the public, who can send medicine and food useful for survival to the tributes. For this reason, when the couple enters the presentation ceremony in the presence of President Snow, the political head of the whole Panem, the stylist Cinna (Lenny Kravitz) chooses to wear special clothes that fill with flames to attract the ‘attention so as not to make them go unnoticed and earn them sponsors.
In preparing for the games, the various tributes follow training and endurance courses. At the end of them each of them receives a score that represents the boy’s chances of victory. Katniss receives the highest score of the session: 11 out of 12. While Peeta receives 8 out of 12. The evening before the start of the games, the tributes are interviewed by the television presenter Caesar Flickerman (Stanley Tucci), and Peeta unexpectedly reveals his feelings for Katniss. Katniss feels outraged, convinced that this is just a method of getting public support.
The games begin and half of the tributes die in the first eight hours. Peeta makes an alliance with the favorites, those from the wealthiest and consequently better trained districts: Marvel and Glimmer (Leven Rambin) (from District 1), Cato (Alexander Ludwig) and Clove (Isabelle Fuhrman) (from District 2 ). These are intent on killing Katniss, but Peeta gives them wrong directions, allowing the girl to stay away from enemies. Katniss continues to move away from the battlefield, but, after being injured in a fire, set by the same strategists to push her to death, she is seen by the favorites. However she manages to escape by climbing a tree and also that night she receives a gift from the sponsors to help her heal her wound. The next day, Katniss makes an alliance with Rue (Amandla Stenberg), of District 11, who indicates to her a genetically modified wasp nest, which is used by the girl to kill one of the favorites, Glimmer, so as to steal her bow and the arrows. Katniss, however, is stung by some wasps and remains unconscious for two days, under the complete supervision of Rue. When the girl recovers, the two study a diversion to destroy the favorites’ stocks. To succeed, Katniss takes the opportunity, using her bow to tear a bag full of apples with the arrows, making them fall on mines placed around the stocks, so as to detonate them. A few hours later Rue is killed by Marvel, killed in turn by Katniss. At Rue’s request, Katniss sings a song to her as she dies and finally raises her hand in greeting to District 11, and this triggers a popular uprising in this same district.
To avoid other riots, the chief of Strategists, Seneca Crane (Wes Bentley), changes the rules of the game under Haymitch’s advice: there can be two winners as long as they are from the same district, giving the people something to cheer on, or the “unfortunate” lovers “of district 12, Katniss and Peeta. Hearing this Katniss searches for Peeta and finds him camouflaged near the river wounded by a sword stroke. The latter makes her understand that he is really in love with her, not only to earn the attention of the sponsors. The next morning, Katniss decides to head to the cornucopia, the place where the games began, as the announcer Claudius Templesmith (Toby Jones) invites all the tributes to a party, where each tribute will find what he desperately has For Katniss it is a medicine to heal the lover Peeta. However, she is stormed by Clove, who attacks her trying to make her die painfully, cutting her face with knives. District 11 tribute Thresh (Dayo Okeniyi) kills Clove, believing her to be responsible for Rue’s death and spares Katniss in memory of Rue. Another tribute, Fox Face, dies by consuming poisonous berries stolen from Peeta. In the meantime, the genetically modified monsters, the hybrids, are released by the Strategists on the playing field and kill Tresh, leaving Katniss and Peeta fighting with the only remaining enemy tribute, Cato. The final clash takes place on the cornucopia, at the base of which the hybrids wait for someone to die in order to then devour it. Cato blocks Peeta in a grip on his throat, but Katniss hits Cato in the hand with an arrow. Peeta takes advantage of the situation to throw Cato off the cornucopia, where he is mortally wounded by the hybrids. To spare him the suffering, Katniss throws an arrow at Cato, killing him permanently. So Peeta and Katniss win the Hunger Games; but the Strategists reverse the regulation again, declaring that only one can win. Peeta asks Katniss to kill him, but she takes the poisonous berries and gives a portion to Peeta, keeping one for herself. Realizing that Katniss and Peeta intend to commit suicide, the Strategists announce that both are winners.
Returning to Capitol City, Katniss is warned by Haymitch that she is now a political target for publicly challenging society’s leaders. Meanwhile, the chief of the Strategists, Seneca Crane, is locked up in a room and forced to commit suicide with poisonous berries for failing to complete his mission of procuring a single winner. As Katniss and Peeta return to their home, President Snow ponders what to do about the two winners and the revolt they unknowingly started.