When thirty-eight-year-old advertising agency owner Brian McCarthy receives a letter from Merton Caldwell, an attorney in Cave Junction, Kentucky, he doesn't realize his life is about to change drastically. A former member of the Navy Special Forces, McCarthy operates McCarthy Communications in Los Angeles; as a teen, however, he spent two summers on his cousin's farm in small Cave Junction, an area replete with limestone caves.
Through a phone call to the attorney, McCarthy learns that his cousin, Joe Thomas, has died, and McCarthy, the closest living relative, has inherited the small farm. McCarthy and his fiancée, Jennie, travel to Kentucky to sort out the details. A letter in Thomas's effects communicates that, before his death, he had discovered a new cave that holds something strange.
McCarthy, who enjoyed the thrill of exploring the Kentucky caves those two summers many years ago, is eager to see what surprises the new cave offers-but he's not the only one who is interested in the cave's interesting contents.