This spinoff series continues its fourth season with "The 1715 Treasure Fleet Part 2," which finds Matty Blake, research partner to brothers Rick and Marty Lagina, heading back to Florida's famed Treasure Coast. Upon arrival, he teams up with professional treasure salvager John Brandon and his team as they begin a dive on the wreckage of the famed 1715 Spanish Treasure Fleet, which was lost to a hurricane off the Florida coast while en route from Cuba back to Spain.