Yeah there is still a few details to work out here and there, some miscommunications to iron out but you all get the general plot here. Will respond more once I am free from work.

As to where the final confrontation happens, I dont think we decided yet. 

I think a lot of this story will focus on what a heart is, what it means to have a heart, how you cant simply replace one because everything that makes you who you are is your heart. A Nobody is just the renains of a person who died, and has lost what makes them who they are, which is why they are disconnected from their past life and who they used to be. But at the same time, new hearts can be created by living life, creating new memories, experiencing emotions. But it is not an easy process once a heart is lost, unless they can reclaim their original heart.