Country lawyer Cameron Scott and wife Mary head to North Carolina's southwestern mountains for a restful vacation and a visit with their daughter, Grae. The day after they arrive, Grae is unexpectedly called into work, so the Scotts book a tour-train excursion; one that travels through a long, curved tunnel. when the lights are extinguished mid-tunnel so the passengers can experience near-total darkness, Jennifer Quinn, the passenger seated next to Cameron, keels over dead. Although Cameron vehemently denies ever having seen or spoken to Miss Quinn before the excursion, the police, and Mary, want to know why his name is on a piece of paper found in the young lady's pocket. When Cameron tries to clear his name by finding out how and why Miss Quinn died, he discovers a disturbing link between her and Grae; a link that puts the whole family's lives in danger. He also uncovers unsettling information about Grae's employer, KaPhaLab, a pharmaceuticals company with customer health last on its list of priorities. Join Cameron as he embarks on another harrowing adventure in the Old North State.