Kingdom Hearts Chain of Memories begins where the PS2 original left off, with hero Sora and his companions Donald and Goofy stripped of their powers in a sudden introduction of a new mystery. Sora must go it alone within a dangerous castle to discover the secret behind the sudden loss of power, with Donald and Goofy lending a hand when needed through the use of attack cards.
During gameplay, Sora can choose his attacks and character aids through a card system, combos and special attacks can be performed as well with the right timing in card choice. As an enemy is defeated, further items and cards can be found to increase abilities.