This book is the final book for Vampire: the Masquerade and covers Gehenna, the end of the world for all intents and purposes. A novel new concept, this book provides multiple scenarios which you can tailor to your needs based on your own needs and likes. No canon, no specifics. Just suggestions, and its a VERY cool concept.
The book starts out with a great piece of fiction using the characters from Cairo by Night, and then gives some general info about Gehenna with stuff like the Red Star, the shattering of the Black Hand and how the sects react. The whereabouts of the Antedilluvians are given (though some are rather disappointing, others are what we've expected all along), though these can be changed to suit your needs. Then the book gives a whole chapter on general setting info for Gehenna. The prophecies and Antedilluvians are examined, including others beyond the 13 "known" ones (though these may or may not just be rumors). Also info on the Inconnu, Jyhad and last daughters of eve, some news clippings from around the world showing how the mortal world is affected and the system for the withering, a new weakness afflicting Cainites in the Final Nights. Info on other supernaturals is largely avoided, but it is mentioned that depending on how it ends it could be a huge spectacle to a quiet bang unnoticed by the mortal world.
The next chapters detail four possible scenarios (which you can adapt for your own use), which I have no intentions of spoiling for you. The first, Wormwood, seems to be the most popular and has God himself taking out his wrath on all vampires. Fair is Foul, probably my favorite, involves Lilith taking her revenge on Caine and his childer amidst the struggles of the Antedilluvians. The next scenario, Nightshade, involves the awakening of the Antedilluvians and may be the "canon" ending to the metaplot from what I've heard on forums. And the final scenario, the Crucible of God, shows what happens when vampires openly take control of human society. And it has a REALLY funny ending if you like ironic justice....
The book closes out with some more stuff, including a Storyteller's guide to running games set in the end times, Stats and profiles for some of the characters presented (which were nice, but some are already presented elsewhere and I guess the space could have been better used in other ways), and finally a last look at Caine himself. Overall, this is a very useful and innovative book. Definately worth running any one of the scenarios presented. The book largely accepts the Caine mythos and Abrahamic religious beliefs (sorry for all those Setites, Laibon, Bahari, Einherjar, etc) BUT makes a big point on how you can change it if you choose. In fact, one of the scenarios includes the Lilith Mythos as I mentioned, which I think is cool. Still, the game is based of the Biblical kinslayer, and it makes sense that the Jewish/Christian/Muslim view of God holds in the game. Overall, just get the book. You and your players will enjoy it.