The Hunger Games
The Hunger Games follows 16-year-old Katniss Everdeen, a girl from District 12 who volunteers for the 74th Hunger Games in place of her younger sister Prim. Also participating from District 12 is Peeta Mellark, a boy who developed a secret lifelong crush on Katniss the moment he laid eyes on her as a child. They are mentored by District 12's only living victor, Haymitch Abernathy, who won the Games 24 years earlier and has since assumed a solitary life of alcoholism. Peeta professes his love for Katniss in a television interview prior to the Games, leading the Capitol to portray Katniss and Peeta as "star-crossed lovers".
Catching Fire
In Catching Fire, which begins nine months after the conclusion of The Hunger Games, Katniss learns that her defiance in the previous novel has started a chain reaction that inspired rebellion in the districts. President Snow is not fooled by Katniss' act and privately threatens to harm her family and friends if she does not help to slow the rebellion, which involves marrying Peeta. Meanwhile, Peeta has become aware of Katniss' disingenuous love of him, but has also been informed of Snow's threats, and promises to help keep up the act to spare the citizens of District 12. As such, they tour the districts as victors and plan a very public wedding. While they follow Snow's orders and keep up the ruse, Katniss inadvertently fuels the rebellion, and the mockingjay pin she wears becomes its symbol.
Mockingjay
Mockingjay, the third and final book, centers around Katniss and the districts' rebellion against the Capitol. Katniss, now a refugee in District 13 and quite damaged from her experiences, agrees to be used by the rebels as a propaganda tool (the embodiment of the mockingjay symbol, complete with costume) to unite the districts in the uprising against the Capitol and President Snow. Peeta and the other remaining tributes captured by the Capitol are rescued, but he has been brainwashed to consider Katniss an enemy, and he is guarded carefully as his rehabilitation progresses. Finally, a group including Katniss, Gale, and a still somewhat unstable Peeta go renegade in the Capitol on a mission to assassinate President Snow. Before Katniss can complete her objective, Prim is killed in a bombing. Later, a captive Snow tells Katniss that Coin, the president of District 13, was behind the bombing, and she deduces that Gale was one of the designers of the bomb.
