During an experiment with a new, revolutionary chemical, chemist Harry Thurston's left hand is turned into a water spout. Bob Blake is called in and another accident turns his entire body into a water spout. Fortunately, a counter-active chemical is used on both and they are restored. Blake decides to take injections of the chemical and become Hydroman, who must then combat a horde of alien invaders led by The Great One.; American reporter Chick Mann uncovers a weapons cache under the Temple of Kali.