The author uses a memoir format to present the history and development of the Submerged Cultural Resources Unit of the US National Park Service (known among divers as the SCRU Team). Lenihan was the founding chief of this archaeological diving team. It begins with Florida cave diving where the author cut his teeth and proceeds through stories of places like Isle Royale, diving the USS Arizona in Pearl Harbor, the atom-bombed wrecks of Bikini Atoll and the CSS Alabama, the confederate raider sunk in the English Channel.