One body. Five suspects. Total darkness.

A tense, claustrophobic historical mystery set almost entirely underground at the onset of the Great Depression about the discovery of a 150-foot waterfall in the middle of a mountain, the unthinkable crime that happens in its caves, and a woman who’s never felt more alive.

In 1928, a Chattanooga man disappears down a hole in the ground and discovers a 150-foot waterfall in the middle of a mountain that he names after his wife: Ruby Falls. Within months, visitors can buy tickets to see the falls for themselves. Ada Smith has been sneaking into the caves at night, entranced by the natural wonders around her and the freedom granted by this new underground world.

But it’s tough timing for a natural wonder. As the country flounders in the Great Depression, a shrewd public relations ploy seems like the only way to save Ruby Falls. A famous mind reader and mystic agrees to launch himself into the Ruby Falls caverns where he will attempt to locate a hidden hatpin using only his psychic abilities. He'll be joined by five others: his manager, his wife, a guide, a Chattanooga businessman, and a reporter from the Chicago Times. But they’re not alone in the caverns. Ada and another guide, Quinton, have been asked to follow the mind reader’s party at a distance, staying out of sight. They are a safety net, in case of a broken leg or busted flashlights.

One of them will be dead before the end of the day.

Faced with a corpse and the stark reality that one of the people in her midst is a killer, Ada needs to get everyone—the murderer and the innocents—back aboveground before their light runs out.

Ruby Falls is both a unique twist on the locked-room mystery and an exploration of loss and what it means to start over. It’s a heart-racing story of survival and a testament to the threads that bind strangers together. Set against the true story of the discovery of Ruby Falls, the novel also draws on the memoirs of Katie Stabler, a female guide at Wind Caves in South Dakota.