Deep Dark — Ann Christy

A lot can change in a century. Graham set the silo free to become a place filled with life and hope in Silo 49: Going Dark. These brave remnants of humanity have forged a new path with no one to guide...or suppress...them. Their silo has changed for the better, but a kinder lie is still a lie and the truth is waiting.
Marina is a Fabricator, recently tasked with reclaiming silver from private hands to replenish the diminishing vault stocks. Among the curiosities turned in, she finds something that should not exist. So begins a search for the most elusive thing in the silo…the truth. Long buried knowledge isn't the only thing unearthed during her single-minded pursuit. Crime, memory-wipes, and even death will stalk the eternal stairwell of the silo.
Silo 49: Deep Dark is book two in the thrilling, post-apocalyptic series set in the WOOL universe.
Books in the Silo 49 series:
Silo 49: Going Dark Silo 49: Deep Dark Silo 49: Dark Till Dawn Silo 49: Flying Season for the Mis-Recorded