After tragedy leaves its mark on Rebekah Hardin’s family, she plans to help her parents and six siblings honor her beloved brother’s memory and alleviate their poverty by working as a guide in the dangerous cave system. Kentucky’s renowned Mammoth Cave presents profitable opportunities for hardworking, capable men. But Rebekah is determined and if it means presenting herself as a himself, then she’s up to the job.

Under the wing of experienced guide Tolly Sanford, “Reb” begins to learn the complexities of the cave. The two are joined by an aspiring young cartographer, Devlin Bale. The university student has traveled to the hill country to map tunnels—not to fall for a girl in disguise.

Can the God who designed miles of underground astonishment shape Devlin’s ambitious plans and free Reb from the weight of her past?