In 2169, people are genetically engineered to stop aging on their 25th birthday, when a 1-year countdown on their forearm begins. When it reaches zero, the person "times out" and dies instantly. Time has thus become the universal currency, transferred directly between people or stored in "time capsules". Several major areas called Time Zones exist within Ohio. Dayton is the poorest, a manufacturing "ghetto" where people rarely have more than 24 hours on their clocks; in New Greenwich, people have enough time to be essentially immortal.