Sora is a young energetic boy looking forward to exploring the world with his friends, Riku and Kairi. The threesome is working hard on completing a raft that will allow them to leave their island but one day a mysterious force causes Sora to gain a special weapon known as the Keyblade. He fights some weird monsters and gets transported to a strange town. Meanwhile, Donald and Goofy leave their castle to search for the king and the chosen one who holds the "key" to saving the world. Sora is attacked again by creatures known as Heartless but is helped out by an old man named Cid and a warrior named Leon. He eventually meets up with Donald and Goofy and they join forces to go search for his friends and the King.

Kingdom Hearts is based on Square's Playstation 2 video game of the same title. The series was reprinted in three volumes as Kingdom Hearts: Final Mix with additional chapters.

The series was first published in English by Tokyopop from October 11, 2005 to July 11, 2006. Yen Press re-published the series as Kingdom Hearts: Final Mix in two omnibus volumes based on the three volume reprint on May 28, 2013.