Winner of the 2012 Nebula Novella Award The year is 2035. After ecological disasters nearly destroyed the Earth, 26 survivors--the last of humanity--are trapped by an alien race in a sterile enclosure known as the Shell. Fifteen-year-old Pete is one of the Six--children who were born deformed or sterile and raised in the Shell. As, one by one, the survivors grow sick and die, Pete and the Six struggle to put aside their anger at the alien Tesslies in order to find the means to rebuild the earth together. Their only hope lies within brief time-portals into the recent past, where they bring back children to replenish their disappearing gene pool. Meanwhile, in 2013, brilliant mathematician Julie Kahn works with the FBI to solve a series of inexplicable kidnappings. Suddenly her predictive algorithms begin to reveal more than just criminal activity. As she begins to realize her role in the impending catastrophe, simultaneously affecting the Earth and the Shell, Julie closes in on the truth. She and Pete are converging in time upon the future of humanity--a future which might never unfold. Weaving three consecutive time lines to unravel both the mystery of the Earth's destruction and the key to its salvation, this taut adventure offers a topical message with a satisfying twist.