First of all there has been a lot of confusion about the release date of this book. Some stores were selling the book last week and so a few people already have the book, but it seems like the release date change from July 16th was so sudden that most stores didn't catch on straight away and so July 9th, tomorrow has basically become the new release date. The book still seems to have a mass market release date of July 29th, so there is a lot of confusion.

the rift part 2

It seems to be purely random if your local store got it in last week or if they will be getting it in tomorrow. My own local comic store is getting it in tomorrow and if I can get a copy I will have a review up on the site. This book is the second of the 3 part series, "The Rift" which is focusing on Toph's relationship with her father, Aang dealing with a factory built on ancient airbender land and Avatar Yangchen's past. Here is the product description.
"Team Avatar find themselves up to their necks in trouble as mysterious forces threaten to destroy land once sacred to the Airbenders! While Aang journeys to the spirit world in search of clues, Toph faces off against her own past!"
And here is the 8 page preview Will you be picking up the book tomorrow from your local comic store?