Shortly after Barry Allen first gained his miraculous powers, and decided to model his alter ego the Flash after his childhood comicbook hero, he accidentally stumbled upon the means to venture to a parallel planet from his own. Naming this world, perhaps erroneously, as Earth-One... he sought out the Flash of this other world... Earth-Two. Knowing the secret identity of the original Flash, Barry introduced himself to Jay Garrick and his wife Joan. It would seem that his journey to Jay's world was well timed, as a new crime wave afflicted his Keystone City, from three of his old foes. Together, the pair set out to capture these three fiendish felons.
While Jay faced his most frequent foe of the golden age, the Thinker... sporting a thinking cap allowing him to emit mental energy to control the actions of others... Barry fought Jay's least common adversary at that period, the Shade. Together, the Scarlet Speedsters faced the Fiddler, and were able to overcome the malevolent maestro's manipulations. In turn, all three crooks were summarily defeated, with Keystone regaining its long held peaceful state. And Barry returned to his own Central City, comforted with the knowledge that his hero actually existed elsewhere in the Multiverse.