Hillary has wanted to see what's outside the colony walls since she was old enough to realize that the world extends beyond. The colonists have been locked safe under the mountain for over a thousand years, yet somehow to Hillary it feels wrong. When she is offered the opportunity to be among the first to live external, she jumps at the chance. But first she'll have to pass a grueling training and education program, withstand the stress of separation from her family, as well as endure the judgment of those who are too afraid to leave the safety of the mountain. On top of all of that, if she and the other recruits don't succeed in re-learning to live outside, the entire colony - all that is left of humanity - may be lost forever.