In 1830s America, Sam, a young woman mistaken for a boy, dares to invade the horse-breeding world of men. She succeeds at first, but witnesses an assault that could destroy her closest friend and tip the balance of power between two monied families: one with social clout, their fortune waning, and one with new money linked to the slave trade.

To save her friend, Sam stays silent, yet in a twist of influence, she's convicted of attempted murder of the "new-money" son, a boy attracted to the boy Sam is thought to be. She's sentenced to uncountable years in Pennsylvania's Eastern State Penitentiary, a supposedly "kinder" prison where each prisoner is kept in strict silence, in a solitary tomb-like cell with one small skylight. ​ As a Quaker, silence has always been healing for Sam, but when time grows amorphous and the guards' attentions turn vengeful, her grip on reality is threatened. A saving grace comes in the form of Willa, up from underground pipes, a prisoner much like herself who keeps hidden in Sam's cell, someone to confide in, someone who knows the worst of what might come. As Sam nears madness, Willa plots the guards' destruction, a plan that will either ensure Sam's release and her own, or end in death for both.

This story of psychological suspense explores the tensions a girl experiences when she wants wider horizons than what the prevailing society deems appropriate. Facing the dangers of entering these uncharted worlds, she's forced to navigate the juxtaposition of truth and illusion, enduring a silence her oppressors turn into a sword, a sword she must learn to wield herself. ​ Based on true conditions in Philadelphia's Eastern State Penitentiary, now closed and turned into a museum, this story serves as a reminder of the problems that persist in prisons across the country.