This is a book that should be labeled required reading for the DCnU launch in September. It reintroduces John Constantine and Swamp Thing back into the DCU just in time for the re-launch. It even introduces on of Constantine's long time associates Chas into the universe.
This book is well written, the only problem with it is that if you don't know who Constantine or Swamp Thing are you may be lost. It does no introductions of the characters other than Constantine remembering Batman from the original Crisis. It brings in Zatanna as well, which is good since she will be part of Constantine's JL Dark come September.
I am not going to spoil the book for you, you need to go to Poe Poz and buy a copy to read, but I will say that it should be read by those who are comics fans and want a glimpse into how the events of the re-launch are being set up. If you have not read DC and are interested for September, it is a good book, but you will need to ask a few questions of your local comic shop staff on who the characters are and maybe get them to explain where Constantine and Swamp Thing have been for 20+ years.
This book gets a 3 out of 5 batarangs from me. If it had more character introduction it would have been higher. I use batarangs instead of stars because a) I am a Batman apologist, b) I am the one writing, and c)they are cooler than stars.
Here is the cover for this issue for those interested.