En route to his wedding, police forensics scientist, Barry Allen, spies a turtle moving at super-human speed. Allen pursues the turtle, as the Flash. Astonishingly, the turtle outpaces the Flash. Pouring on the speed, the Flash feels himself tearing through inter-dimensional space. The Flash materializes on a strange world. One where all of it's inhabitants possess super-human speed. Returning to Earth, the Flash discovers that, while he was only on the alien world for two minutes, five hours have elapsed on Earth. His bride-to-be, Picture News reporter, Iris West, is furious that Allen has stood her up at the altar. West breaks up with Allen, vowing to never see him again. Allen's crushing heartbreak leaves him feeling lonely and despondent.
Allen blames his alter-ego, the Flash, for ruining his relationship with West. Allen nails his Flash costume to a tree, and leaves a sign declaring his intention to retire his Flash identity. As Allen walks away, tears seem to stream down the eye-holes of the costume's mask. Allen tracks down West, at an isolated mountain retreat. Seeing West menaced by a large bear, Allen intervenes. Refusing to use his super-speed, Allen is viciously beaten down by the bear. The bear turns out to be a retired, runaway circus performer, and thus Allen is not unduly injured. West is not happy to see Allen. Having transferred her affections to the Flash, Allen finds that he is his own rival. Allen's Flash costume is discovered, then placed on display at the Flash Museum.
Near closing time, Allen stands alone before his Flash costume. Incredibly, he seems to hear the costume speaking to him, begging him to resume his career as the Flash. Allen even believes he sees tears pouring from the eye-holes of the mask. Giving in to the inevitable, Allen dons his Flash costume once more. Suddenly, Allen realizes that he isn't alone, and turns to see West standing behind him. To make matters worse, a gang of thugs enters and takes West hostage. The Flash easily beats down the would-be thieves, planting a kiss on West's lips as he does so. West stands transfixed, believing herself hypnotized into thinking that Allen really was the Flash. Dismissing the evidence of her own eyes, West resumes her romance with Allen, still not knowing that he is, in fact, the Flash.
By accident, the Mirror Master creates a mirror that reflects 20 seconds into the future. Testing the reflection, the Mirror Master finds that no action can change the future reflected in the mirror. The Mirror Master steals Cleopatra's Mirror from the Petty Art Gallery. When the Flash inevitably arrives to capture the Mirror Master, he finds himself holding the fading remnants of a reflection. A second encounter goes no better. Once again the Mirror Master successfully completes a crime, and escapes, leaving behind another mirror image for the Flash.
Using his Cosmic Treadmill, the Flash races three days into the future. Discovering the Mirror Master's hideout, the Flash attacks the his old foe. The Mirror Master, though, has already seen the Flash coming, in his future reflecting mirror. The Mirror Master gets the drop on the Flash, and seemingly vaporizes him. The Mirror Master has barely any time to gloat over his victory, when he hears the Flash's voice behind him. The Scarlet Speedster quickly destroys the future reflecting mirror, then beats the living daylights out of the Mirror Master.
In an interview with Picture News reporter, Iris West, the Flash reveals how he triumphed over the Mirror Master. As the Mirror Master fired upon him, the Flash ceased the internal vibrations keeping him three days in the future, and immediately returned to the present. The Flash then waited the three days, to secretly return to the Mirror Master's lair. After watching himself seemingly be killed by the Mirror Master, the Flash stepped in and defeated his old foe. Back at the Petty Art Gallery, the Flash, as Allen, tells West that he can see a future image of himself, in Cleopatra's Mirror, kissing West. Before West can protest, Allen fulfills his future.