Holy cow! I've heard this book get hype, mostly from my teens, but I didn't realize how right they were until I finally plunged in! This book is fantastic! The concept is insanely unique, and the whole story is inventive and over the top amazing! In a world where humans have finally overcome disease, old age, war, and injuries there is nothing left to fear or learn. People can reset their clock and be younger, they can also reset their nannites to have higher metabolism, adjust hormones, depression, and other maladies. They can even be brought back to life from extreme accidents. There is nothing to fear, except for the scythe. Since humanity has overcome every obstacle, the only problem now is overpopulation. The scythe are tasked with random killings to keep the world in balance; they are a terrible necessity. Two teens are about to get real intimate with the dark side of humanity when a scythe has chosen them to become his apprentices. They must learn the best ways to "glean" (killing is a dirty word), and how to do so with humanity and humility. A wonderfully different book. My review will not do it justice!