In the year 2274, the remnants of human civilization live in a sealed city contained beneath a cluster of geodesic domes, a utopia run by a computer that takes care of all aspects of life, including reproduction. The citizens live a Hedonism life but in order to prevent overpopulation within their limited resources, everyone must undergo the rite of "Carrousel" when they reach the age of 30. There, they are killed under the guise of being "renewed.” To track this, each person is implanted at birth with a "life-clock" crystal in the palm of the hand that changes color as they get older and begins blinking as they approach their "Last Day.” Most residents accept this promise of rebirth, but those who do not and attempt to flee the city are known as "Runners.” An elite team of policemen known as "Sandmen,” outfitted in predominantly black uniforms and serving in an agency of the city called "Deep Sleep,” are assigned to pursue and terminate Runners as they try to escape.