Millions of people have disappeared in an instant from the earth, including Mark Hillag's missionary parents, Caleb and Sarah Hillag, and his sister Esther. Mark is left alone in a world suddenly turned upside-down. When he tries to escape from Mexico City to return to the States, a Marine commandeers Mark and his car to take him to a Mexican resort town. There, Mark meets Nikki Savage, whose parents have also disappeared.Thus begins Mark and Nikki's story of flight and survival, life and death, as one by one the Tribulation's Seven Seals, described in the Book of Revelation, are opened. Can Mark and Nikki survive in a world that is increasingly growing more hostile and deadly? Following the unfolding and gripping adventure is Tribulation's Seven Seals: Farmer and Emile's Great-Great Grandson Mark, the fifth book of seven in the Strangers and Pilgrims series, which chronicles the lives and challenges of four generations of the Trevor Family.