Another Key

"Another Key" is the post-credit ending of Kingdom Hearts Melody of Memory. It uses in-game graphics and voice acting and ends with the phase "An Oath to Return".

Synopsis
At the Mysterious Tower, Kairi informs Yen Sid, Mickey, Donald, and Goofy about Riku's decision to go alone to Quadratum to look for Sora. Mickey, worried about Riku in a unknown world, tries to go after him but is stopped by Donald, Goofy, and Yen Sid. Yen Sid learns from Kairi that Terra-Xehanort had been researching the "fictional world" since his time as an apprentice, but with the defeat of Xehanort, there is no one else who knows anything about it. Yen Sid recalls from his days as a Keyblade Master that in the past, ancient Keyblade Masters had also crossed into the other world and that Terra-Xehanort had been looking more deeply into it.

Yen Sid then tasks Donald and Goofy to gather the other Keyblade wielders in Radiant Garden, the Land of Departure, and Twilight Town to stop searching for Sora and inform them about what they have learned. Kairi, wanting to go back to her Keyblade training, wishes to learn under Aqua, which Yen Sid approves. Finally, Yen Sid tasks Mickey with learning about Quadratum and how it relates to the ancient Keyblade Masters by sending him to Scala ad Caelum.

An Oath to Return

KINGDOM HEARTS

Characters in order of appearance

 * Riku, Terra-Xehanort, Xehanort, Sora, and Aqua are mentioned.

Unlock criteria
"Another Key" is unlocked upon clearing Melody of Memory's End in World Tour.