Columbia's 34th serial production starring Buster Crabbe, the Serial King himself, who had the lead in five from Universal and two for Columbia, was based on the radio serial,("Captain Silver's Log of) The Sea Hound", heard on the Blue Network 1942-44,on Mutual 1946-47 and, briefly on ABC in 1948, and also the comic book (six issues across four years) that had little demand in 1945-49 and not much now among Golden Age collectors, with Crabbe, playing Captain Silver and getting more money for it than producer Sam Katzman paid for the rights to use the character, and some claim the copyright owner may have paid Katzman to use the character. Captain Silver and his friends --- Jerry and seagoing cowboy Tex and a Chinese inventor named Kukai --- are cruising through tropical waters, between California and Catalina, aboard the "Sea Hound" when they pick up an SOS from the yacht "Esmeralda." Silver sails to Typhoon Cove and finds the yacht under attack by "pirates." Aboard the attacked craft are Ann Whitney, yacht owner Stanley Rand and Vardman. Silver and crew beat off the attackers and he learns that Ann is searching for her father, John Whitney, who vanished into the jungle during a search for a fabulous treasure of Spanish gold. Later, Silver discovers the "pirates" are in the employ of a sinister master-criminal known as the Admiral. Using a map in Rand's possession, Silver locates the treasure chest when he descends to the ocean floor in a diving suit, but finds it empty. 14 water-logged, none-too-thrilling chapters later, Silver locates the treasure, rescues Ann's father and puts an end to the Admiral and his henchmen, including Rand and Vardman who veteran serial-watchers had an eye on as far back as chapter 1.