Ok let me try to ACUALLY explain what the game is...
It's about a boy named Sora who lives on this island, its acually a world known as Destiny Islands, with his two friends Riku and Kairi who long to see other worlds. One night, Sora finds that his home is being destroyed by creatures of the dark, known as the Heartless, and a strange weapon known as the Keyblade (shaped as a Key
) appears and he uses to kill off some Heartless. After he defeats a giant Heartless, he finds himself in a town, which is acually another world where people who have lost there worlds to the darkness wander off to if they managed to survive, where he meets up with Donald and Goofy who were looking for the "key bearer" that their king, obviously everyone's favorite animated mouse,had told them to find in a letter before he mysteriously vanaged. It turns out that the Heartless are creautres who steal hearts from people and they become heartless, and if strong-willed they make Nobodies too but thats in Kingdom Hearts II, and if they steal hearts from worlds, the worlds vanish from existance. So the three new friends go out into disney movie themed worlds as Sora tries to find his two friends and while Donald and Goofy try to find The King, and of course help out the disney characters fight the anataganist, usually, from the movie and lock the Keyhole of the world so the heartless won't destroy it. Of course there are some great twists on the way that I'm not going to spoil for you and I HIGHLY recomment you play it! SUPER MEGA ULTRON HIGHLY!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
This is the first game info, the second has more but you get the general idea. Also, Kingdom Hearts in the game is the world to all hearts, the thing that the anataganists want for power.
Hope that helps!