Clay Jannon, a recession-afflicted web designer, takes a last-resort night-shift job at a 24-Hour bookstore—the main requirement being the ability to quickly climb a ladder up three undivided stories of bookcases. Though immediately taken with Mr. Penumbra, the elderly proprieter, Clay can't help but notice that the store is a very strange one: less concerned with making a profit selling the negligible stock in the front, and more with facilitating the borrowing of huge, gibberish-filled books from the massive shelves in the back.

Working on upgrades to the store's ancient inventory software, Clay uncovers the puzzle these books are hiding—and accidentally solves it. The next day, the store is closed, Mr. Penumbra is nowhere to be found, and Clay and his Silicon Valley friends go off on an adventure that will become a struggle between the old and new, the past and the future, in which the goal is not to win but to learn to work together.

This book is combination slice-of-life, science fiction, and D&D quest adventure, full of both historic exposition and futuristic-sounding science and tech. Some of it is true, and some is fiction, but because true things can sound so implausible, and fiction can seem so real, it's impossible to tell which is which without stopping to Google every few minutes. It keeps you a little off balance, and gives the whole book a fun surreality.