"Every hotel has a room it doesn't rent. Ask the front desk and they'll tell you it's storage, or mechanical, or simply doesn't exist... But sometimes that room has a bed, and a lock, and a guest who checked in under a name that belongs to no one."

Devon Morgan is a residential real estate appraiser accustomed to exposing structural flaws and measuring the distance between what is shown and what is hidden. Following her estranged mother's death, Devon inherits a row house in Savannah, Georgia, along with a cryptic final instruction written in the margins of her will: Sell the house and do not stay at the Marlowe.

Ignoring the warning, Devon books a room at the historic, beautifully restored Marlowe House hotel. But while unpacking, she makes a chilling discovery: a heavy brass skeleton key sewn securely into the lining of her mother's old travel bag, stamped with "MH-0".

Using her architectural expertise, Devon tracks the key to a windowless space on a half-landing?"Room Zero"?a room that does not exist on the hotel's modern renovation blueprints. Inside, she finds a woman waiting for her with a stack of unsealed letters detailing a brutal crime that occurred in the building twenty-six years ago, a silenced witness, and a dark cover-up.

But when Devon returns the next morning, Room Zero has vanished. It has been completely sealed behind freshly built, still-wet drywall.

Trapped in a cat-and-mouse game with a charming hotel owner who tracks her every move, Devon must use her professional skills to literally and metaphorically tear down the walls of the property. What she unearths is a predator living under a forged identity, a corrupt institutional system, and the devastating truth that her own college education and career were secretly funded by a trust fund of hush money.