Catching Fire Spoiler From Wikipedia!:

WIKIPEDIA-Katniss and Peeta are again living in District Twelve, but now in large houses in the area of the district called the "Victor's Village." Katniss has found that she cannot go back to the same life that she had before the Games. She no longer has the same easygoing relationship with Gale that she used to. And everyone seems to think they are cousins. On the day that she and Peeta are to start their victory tour of the country, she is visited by President Snow. Snow is angry because of the way she defied the Capitol, when she and Peeta decided to eat poisonous berries instead of one having to kill the other at the end of the Hunger Games. President Snow tells Katniss that when she defied the Capitol, she started a chain reaction and that other districts are likely to rebel. He threatens to kill Gale if she cannot prove to everyone in Panem, including himself, that it was not an act of defiance, but that she was too madly in love with Peeta to do otherwise.

Katniss is reunited with her prep team and Cinna, her stylist. Cinna has been helping Katniss develop her "skill" which every tribute is supposed to have. Katniss has no skills that she believes are worthy of note besides hunting. So she opts to work on clothes designing. She shows off the clothes that she designed to a group of reporters and then is sent to the train where she will travel to the various districts. On the way, Katniss confesses to Haymitch, her mentor, about the meeting with President Snow. Haymitch points out to her that she must be a mentor to other tributes in the future, and that the people of Panem are never going to forget what happened between her and Peeta in the arena. He reminds her that she must continue to be "in love" with Peeta until she dies, or the people will get suspicious and the Capitol will have a reason to dispose of her. Katniss realizes that it probably means she will have to marry Peeta.

The first stop on the tour is District Eleven, where Katniss' friend and ally, Rue was from. Everyone gathers in the town square to listen to the mayor's victory speech, and Peeta's own comments. As they are being escorted into the building where they will have their victory feast, Katniss decides that she needs to say something. Peeta already gave his thanks to the families of Rue and Thresh by giving each family one month supply of his winnings every year for the duration of his life. Katniss says a quick speech, thanking District Eleven for their tributes, the boy tribute who saved her life in the arena. When she is done, a man whistles the four note tune that Rue used to tell everyone that the days work was over, and used in the Arena to tell Katniss 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. She is taken into the building but not before she sees Peacekeepers drag the man up the steps into plain view of the crowd, and shoot him in the head.

Katniss and Peeta then proceed to travel to all of the twelve districts before returning home. During an interview, Peeta proposes to Katniss publicly, hoping to settle the dispute between Katniss and President Snow. However, after they return home to District 12 it is announced that in honor of the Seventy-Fifth Hunger Games, twenty-four of the remaining Hunger Games victors will be forced back into the arena to fight to the death, yet again. Katniss then realizes that it will be her job to protect Peeta by any means possible. During a final interview the day before the Quarter Quell, Cinna creates a dress that goes from being a wedding dress to a dress styled after the mockingjay, which has become a symbol of hope and rebellion among the Districts.In a final attempt to escape the arena, Peeta tells a reporter that Katniss is pregnant with his child, which causes much mayhem in the Capitol. However, Katniss and Peeta are forced into the arena anyway. Before Katniss is sent into the Arena, she is forced to watch Cinna brutally beaten and dragged off as punishment for the dress he created. His fate isn't revealed in the book, though he isn't seen or mentioned again.

Katniss and Peeta then join up with two other victors, Finnick, a twenty-four-year-old man who is known to be one of the youngest Hunger Games victors, after successfully surviving the games at only age fourteen, and Mags, an eighty-year-old woman from District 4 who volunteered to take the place of Finnick's lover, Annie during the reaping.

Katniss and Peeta survive many hardships, including an acid fog that Mags voluntarily walks into to die after they realize that she cannot be carried any farther. After Mags' death, Katniss, Peeta, and Finnick join forces with Johanna Mason, a sarcastic and often cruel female victor, and Beetee and Wiress an older couple who have been said to be, 'exceptionally smart'. Wiress soon proves her genius status true after revealing to Katniss that all of the arena's disasters (tidal waves, blood rain, acid mist, monstrous monkeys, jabberjays, insects, a "beast," and electrical storms) appear to be on a timed chart that restarts at midnight.

After an attack by two other victors, Wiress is killed and her corpse is swept out to sea. Katniss then has to swim out and find Wiress and retrieve an electrical wire from her body before the hover craft carries her off. Later on, Katniss finds out that the wire was merely the beginning of a plan Beetee was formulating to kill three other tributes, using one of the disasters (lightning) and harnessing it's power with a wire in order to electrocute the other contenders.

In the final chapters, Katniss, Peeta, Beetee, Finnick, and Johanna attempt to carry out Beetee's plan to electrify the other contenders. However, Katniss become paranoid that Johanna and Finnick are planning to murder Peeta and herself after she is shoved down to the floor by Johanna, who proceeds to rip into Katniss's arm with a knife, causing Katniss to lose a large amount of blood. She stumbles through the jungle in order to find Peeta, worried Finnick has already killed him.

She finds Beetee has been knocked unconscious, having tried to disable the force field with an electrified knife. She uses the last of her strength to fire an electrified arrow at one of the arena's force fields which results in her paralysis. When she wakes up she is being transported to District 13, a place she was told no longer existed. She is informed that there had been a plan to break out of the arena before the games even began between most of the contestants, that Beetee had been attempting to destroy the force field the same way she did, and Johanna had only stabbed her arm in order to tear out the tracking chip that the Capitol used to follow her movements. Peeta, Johanna, and Enobaria have been captured by the Capitol. She is later informed by her best friend, Gale, that District 12 has been bombed and destroyed but that he got Prim and Katniss' mother out in time.