This takes place after Kingdom Hearts 2 but before Kingdom Hearts 3D. New worlds have been found and with them new adventures. The enemies that mainly trouble these new worlds are the Heartless and Nobodies lead by a new Organization. The people from these new worlds seem to also have some way to travel through worlds do to various means.
The new Organization has it's operations based out of The World that Never was. The new leader is a mysterious nobody known as Xero who seems to be a lower class of Nobody.