Old Man's War

With life nearly over at 75, John Perry takes the only logical course of action, and joins the army. The Colonial Defense Force (CDF), Perry's service-of-choice, has extended into outer space to pave the way for human colonization of other planets while fending off marauding aliens.

The CDF has a trick up its sleeve that makes enlistment especially enticing for seniors: the promise of restoring their youth. Perry finds himself in a new body crafted from his original DNA and upgraded for battle, including a brain-implanted computer. Soon, Perry must fight for his life on various alien-infested battlegrounds.