There is just a hint of Vonnegut in Shades of Grey paired with the newly popular theme of, "our future society is hiding something that happened in the past that would prove the people currently in power are evil." It's pretty great.
Let me first preface this biased review by telling you Jasper Fforde is one of my favorite authors. His stories are smart, funny, and very in-depth. His characters are witting, awkward, and treacherous. His stories are the complete package and his worlds are always fully imagined.
Shades of Grey takes place in a society pretty far into our future. Humanity has mutated so their eyes no longer dilate to see at night. They also can only see one hue of color and in varying percentages of fullness. If a person's bloodline stays relatively pure - marrying those of like color - offspring have a high percentage of visibility in their specific color. If two people who have visibility in different primary colors marry, their children will see a secondary color. If too much mixing between colors occurs offspring will eventually see no color and become a grey.
Edward Russett (a red) and Jane Grey (guess what color she sees) are our leads in a small town on the fringes of society. Russett (I love that Fforde gives all these characters last names that relate to how much of their color they can see) has come to town with his something-of-a-doctor-father who uses color samples to ignite physical reactions in people and keep them healthy. Eddie meets Jane who, after threatening to kill him a few times begins to open his eyes to the cover-ups and corruption taking place in their world. The impression this enlightenment leaves on Eddie is pretty severe due to his strict moral compass and his blossoming love for Jane. He joins the "resistance" and gears up to infiltrate The Collective.
We don't really find out much about the resistance but I can tell you honestly that society created after the "Something that Happened" has issues. When your motto is, "Apart. We are together," you know things are being covered up.
After a few deaths, plenty of secrecy, and lots of subterfuge we arrive at the end of a very exciting and unusual story that's really just the beginning of what I'll assume is going to be a great adventure.