The StoryThe Lion King was unique when it was made as it was the first story that Disney had written. It wasn't based on a well known story, fairy tale or myth. (Although some people argue that it is the story of Hamlet told in the animal world)
The story begins with the newborn lion cub, Simba, being held aloft by the monkey Rafiki, atop Pride Rock. Simba is the sole heir of the King of Pride Rock, Mufasa, and is, therefore, destined to rule the Pride lands when his father dies. Unfortunately, his uncle Scar also wants to be king. Simba, with his young female friend, Nala spend the first part of the movie getting into trouble, and being bailed out by the bird Zazoo.
Scar, through carefully planned scheming, manages to trap Mufasa and kill him using the young Simba as bait. He convinces the impressionable young cub that the death is all his fault. Simba runs away to the desert and nearly dies. He is rescued by Timone (a meercat) and Pumba (a warthog) who teach him to forget his past and live for the future. As Simba grows he forgets his friends and family at Pride Rock.
Back at Pride Rock, Scar rules like a tyrant with an army of hyenas. He destroys the natural balance by over hunting the pride lands, forcing the lionesses to hunt further afield. On one such hunting expedition, Nala inadvertantly stumbles on Simba and love blooms.
Nala convinces Simba to go back to Pride Rock and save his kingdom. With the help of Timone, Pumba and Nala he realises that it was Scar who killed Mufasa. He fights a fiery battle with Scar and kills his uncle and exiles the hyenas.
The movie ends with the circle of life coming full cycle as Rafiki holds Nala's and Simba's newborn cub aloft to be accepted by the animals of the Pride Lands as their future king.