Eleven Days on Earth by Jerry J. Davis
Jon August is dead.
If that weren't bad enough, the place he lands in the afterlife is one where souls prefer vodka, not beer. That's a problem because Jon is a beer lover. Not just any beer, either. Good beer. Great beer. Because he knows that mankind's civilization owes everything to beer. It's the actual Holy Water.
Jon meets and falls under the spell of a mysterious goddess who helps him find his way back to the land of the living. Under the Bridge of Eternity, through the Sands of Time -- to emerge not as a ghost, but a living mortal, one who can die again.
His mere presence upsets the balance of our world, and Jon finds himself a pawn in a power struggle between the modern gods -- in particular, the feuding daughters of Time and Fate. One is acting as his guardian angel, while the other is trying to kill him. Jon must stay alive long enough to find the Holy Beer and, in the process, stop the power grab being made on our Universe -- a struggle where not only is humanity's fate hanging in the balance, but also the fate of our eternal souls.