The book begins by introducing Bill Nagle, a seasoned deep-sea diver and captain living in Brielle, New Jersey. Brielle’s population mostly caters to tourists, but some inhabitants who live there year-round make their living by fishing. Nagle is the captain of the Seeker, a charter diving boat that he uses to investigate shipwrecks off the coast of New Jersey. Nagle made a name for himself when he was a young man by excelling at deep-sea shipwreck diving, an extremely dangerous pursuit. His most infamous feat involved recovering the huge bell from a passenger liner, the Andrea Doria, which sank in 1956 near Nantucket Island. In 1991, Nagle still took divers out on the Seeker to the wreck of the Andrea Doria, but as time progressed Nagle lost diving clients due to his alcoholism and his abrasive attitude toward amateur tourist divers. He believed that the commercialism of modern diving obscured the true heart of deep-sea shipwreck exploration, which involves risking life and limb simply for the privilege of discovering something new.

Nagle, while at his favorite bar, the Harbor Inn, met with a fisher acquaintance, Skeets. The two men struck up a bargain to trade coordinates of shipwreck locations. Shipwreck divers and fishers alike jealously guard such coordinates.