Marine biologist and filmmaker Rick Rosenthal dives into the myths and mysteries surrounding the sailfish, swordfish and marlin whose power, speed and grace have long captured the imaginations of anglers everywhere. Rosenthal and his crew meet the mighty fish on their own turf -- in the waters of two different oceans -- over the course of two years in this "deep" episode of the PBS favorite, "Nature." Actor F. Murray Abraham narrates.