KINGDOM HEARTS III is the final installment of the “Dark Seeker Saga”, which has spanned all of the previous releases, including KINGDOM HEARTS, KH Chain of Memories, KH 358/2 Days, KINGDOM HEARTS II, KH Birth by Sleep, KH Re:Coded, KH Dream Drop Distance, KH 0.2 Birth by Sleep ~A Fragmentary Passage~, KH Union χ, and KH χ Back Cover. As such, familiarity (at a bare minimum) with ALL of these previous titles is a MUST in order to fully comprehend the story of KINGDOM HEARTS III!
After the events of KH Dream Drop Distance, the stage has been set for another Keyblade War to begin. Master Xehanort has returned and has collected 13 beings of darkness to use as vessels in order to clash with the 7 Guardians of Light needed to reforge the ultimate weapon and protector of the one true Kingdom Hearts, the χ-Blade!
Meanwhile, Sora has been stripped of most of his power after almost being made into one of Xehanort’s vessels, and must travel with Donald and Goofy to various worlds in order to regain his strength and gain mastery of a crucial skill needed to turn the tide against Master Xehanort and the new Organization XIII: the Power of Waking.
As Sora, Donald, and Goofy journey, Riku and King Mickey make their way into the Dark World in an effort to rescue Master Aqua, but the Heartless prove too much for them and they are forced to retreat. They return to Radiant Garden and work with Ienzo to gather more information from Ansem the Wise’s research.
As the two groups walk their separate paths, they eventually join forces to rescue Aqua from the Dark World. With Aqua retrieved, the group travels to the Land of Departure to reawaken Ventus, whose heart has been sleeping inside Sora’s since the events of KH Birth by Sleep.
Sora, Donald, Goofy, Riku, Mickey, Aqua, and Ventus travel to the Keyblade Graveyard, along with Kairi and Axel (who have been training to wield their newfound Keyblades with Merlin since the events of KH Dream Drop Distance) in order to confront Master Xehanort and his 13 vessels of darkness. The resulting battles are long and grueling, and along the way, old allies return to aid the 7 Guardians. The final battle for the fate of Kingdom Hearts, and the fate of the World, comes to its climactic conclusion!