Kingdom Hearts IV: Return of Union Cross

You wake up on a strange island full of light with no memory of who you are and you have lost your sense of voice. You encounter people you aren't familiar with who wield Keyblades, and are surprised that you too can wield one. After that, you suddenly encounter a being like you, but is tainted with darkness. And as you begin your journey across new and strangely familiar worlds, that being isn't the only threat you will face . . .
Join Sora's friends old and new, and many more characters across the worlds as you struggle to reclaim your identity and battle against the most powerful, yet unexpected, enemies from the past that threaten to tear the worlds apart.