In the original Kingdom Hearts, you got to use Simba as a summon but now you will be able to visit Simba's world, "Pride Rock", and visit the whole cast of Lion King. As suspected, the storyline will follow closely to the Lion King movie.

Instead of Sora and company being in their normal form in this world, upon entering the world, Sora will turn into a cub, Donald turns into a creature that resembles Zazu and Goofy becomes a turtle. The storyline of Lion King is that when Simba learns one day that he'll become King, his father Mufasa, begins to educate Simba on the circle of life. This is when Mufasa's younger brother, Scar, becomes jealous of Simba's position of heir. Scar teams up with the Hyenas to get the throne of King himself.

This is where Sora and the gang comes in. Sora teams up with Simba to get revenge on Scar and eventually, we see Scar team up with none other then Pete. We get to notice a pattern here how Pete always becomes allies with the enemy. Also in this world, you'll be able to converse with Rafiki, Timbon, Pumbaa and Nala.