Three generations of reckless and unsustainable development have transformed the future environment into an almost total wasteland. Refugees from the future have found a way to return to the past, but the impact of these 'immigrants' on present-day resources has led to the formation of citizen watch groups, who are determined to stop these time-travelers at any cost. Jackson, the teen-aged son of one of these bounty hunters, is enlisted into his first patrol--and is forced into a brutal choice between his father's principles and his own sense of humanity.