In a futuristic world, there are few human societies left on the planet. Those which survived are largely slaves to the all powerful Capitol.
Once a year, they each must send two of their children to fight to the death in a gladiatorial style arena. It's gruesome entertainment framed as reality TV for the delight of the Capitol's citizens. But it has a secondary purpose too.
The Hunger Games - as these juvenile killing fields are called - stand as a stark reminder to all of the Districts that they remain in thrall.
Their very lives continue at the whim of President Snow, the Capitol's tyrant. Their children's lives are nothing more than sport for his people. The whole show is framed as punishment for an uprising seventy-four years ago. It is a vindictive and bloody message that the Capitol has the power to quash any repeat of that.
The enslaved twelve Districts are kept in want of basic sustenance, while the Capitol flaunts its wealth and leisure. District One is given a little more, as it keeps the Capitol in jewels and luxury items. Each area is allotted progressively less, until we are informed that many people die in the streets of starvation in lowly District Twelve.
There can only be one victor in the elaborate arena. Only one child can successfully traverse its forests, lakes or whatever terrain the Gamemakers create. Traumatized and damaged beyond recall, the winner takes home something special - food.
His or her entire District gets extra provisions of grain for one whole year, until the slaughter begins again.
This is why it's called the Hunger Games. The fight for survival is bigger than the arena itself.