Harry Thurston, a young chemical engineer, accidentally compounded a formula to convert human flesh and blood into water. A huge container of this remarkable solution was spilled and splashed over Bob Blake, Harry's friend, causing him to disintegrate and become a pool of water on the laboratory floor! Promptly, an antidote was concocted, and with the aid of this, Bob regained his natural form. He then discovered that he could control this phenomenal change merely by the power of thought. Hydroman had a sidekick named Rainbow Boy until he went on to be a solo hero.