Here's a breakdown of how it relates to the story:
* The Setting: Panem is a dystopian nation that was formed after a great war. It is a post-apocalyptic society that has divided its population into 12 districts and a wealthy Capitol.
* The Hunger Games: The Hunger Games are a brutal televised event held annually in Panem. The Capitol uses them as a means of control and entertainment, forcing each district to send two tributes (one boy and one girl) to fight to the death in a giant arena.
Essentially, Panem is the world in which The Hunger Games take place. It's not an object or a tool, but the oppressive society that dictates the rules and reality of the Hunger Games.