But I'll give you a few hints.
Frodo has carried the Ring through a long and arduous journey to the cracks of Mount Doom.
On this long and arduous journey, Frodo has been stalked by a horrid little creature that was once what he was - a Ring-Bearer. The horrid little creature, called Gollum, has become obsessed with the Ring and wants it back. He follows Sam and Frodo, and serves them to the best of his ability so as to be close to the Ring. But eventually he betrays them and tries to have them eaten by a giant spider, so as to claim the Ring back. However, they survive and escape.
So here we are, at the crack of Mount Doom. Frodo is about to throw the Ring in and destroy it, when he decides that actually he will keep the Ring for his own power and aggrandisement. But all this time, Gollum has been sneaking along behind them. He leaps - and snaps! - and the Ring is his.
For a while, anyway.