Johnny Sokko and His Flying Robot: 1 - Dracolon, The Great Sea Monster

Giant Robo (ジャイアントロボ, Jaianto Robo), also known as Johnny Sokko and His Flying Robot in the United States, is a manga and tokusatsu series created by Mitsuteru Yokoyama. It is similar to Yokoyama's Tetsujin 28-go (known as Gigantor in the U.S.), but Giant Robo has more elements of fantasy. The original 26-episode tokusatsu TV series, produced by Toei Company, aired on NET (later renamed TV Asahi) from October 11, 1967 to April 1, 1968.
Shipwrecked, Daisaku Kusama (called Johnny Sokko in the American version) and Juro Minami (called Jerry Mano in the American version), an agent for the organization Unicorn, drift to an island which proves to be a base of the BF Syndicate (called the Gargoyle Gang in the American version), an extra-terrestrial terrorist group from the planet Gargoyle, who are bent on conquering Earth in the name of their leader, an alien known as Emperor Guillotine. They happen to discover a huge robot created by for the BF Syndicate while they are escaping. Meanwhile, Emperor Guillotine commands the BF Commander Spider to send Dakolar, a monster that destroyed Daisaku and Minami's ship the other night, on a mission to attack Tokyo, the city of Unicorn's main headquarters. Now under the control of Daisaku, will Giant Robo destroy Dakolar (Dracolon in English version) before Tokyo crumbles under the weight of the monster's enormous might?