For as long as Cassie Hunt can remember her Aunt Aggie has spoken about the forgotten world that exists just below their feet, in the tunnels and catacombs of the Sand House. The story is what inspired Cassie to become an archaeologist.
But Aggie has a secret that she’s buried as deep as the tunnels and when excavation work begins on the site, Cassie is the only one who can help her keep it.
With the assistance of her old university friend, Noah Flanagan, she puts into action a plan to honor Aggie’s wishes.
It seems the deeper Noah and Cassie dig, the more shocking the secrets uncovered – and danger is never far away, both above and below the ground.