Book One of the Silo 49 series, set in Hugh Howey's WOOL universe.

Silo 49 has never had it easy and things have just gotten a whole lot worse. Graham, the head of IT, has done many unsavory things in his life but everyone has a line they won't cross. He just found his. With only his best friend, Wallis and a dying electrician, Grace, to stand by him, he is left with one clear and final choice. Does he do what is right or what the rules say he should? It is a race against time for the trio against the impersonal might of Silo One. Their only choice? Going Dark.