Ender in Exile by Orson Scott Card
I'm honestly not sure this book needed to exist. While it does tie up all the dangling plotlines from the Shadow series, the book as a whole doesn't really have any driving conflict. It's more just "here's what happened to Ender in the immediate aftermath of the Bugger War." There are two seeming conflicts in the book, but they both seem manufactured, just to give Ender something to do.
Thrilled as I am to have another Ender book, I think it would have been better if the Bean stories had just been wrapped up in a novelette, or even better, at the end of the last Shadow book.
Perhaps the main conflict I'm missing is an internal one within Ender, where he has to confront the killer inside, but that conflict was wrapped up pretty nicely, I thought, in the actual Ender's Game sequels.