“HERE LIES THE FLASH – DEAD AND UNBURIED.” Dr. Light has mastered a method of using light as a disguise, which allows him to battle the Flash disguised as the Green Ghost, a spider, Dexter Miles and even a pile of jewels.
Picture News reporter, Iris West, is writing an article on Foundling House. Particularly heartbreaking to West is the story of Beth, a lost, five year old girl, with little memory of her early life. West's husband, police forensics scientist, Barry Allen, has his own problems. A new thief, the Green Ghost, has been looting Central City. While West is driving Allen to work, they see the owner of a jewelry store, crying out that he is being robbed by the Green Ghost. Allen investigates, as the Flash. Racing into the store, the Flash finds no trace of the Green Ghost. The jewelry store owner, Charles Perkins, is relieved to discover that his souvenir chess piece has not been taken.
Unbeknownst to the Flash, the Green Ghost is standing right next to him, appearing as a small spider. Back at his secret lair, the spider illusion is dropped, revealing the true culprit behind the Green Ghost's crimes, Doctor Light. Having faced separate defeats at the hands of the Justice League of America, the Atom, and the Green Lantern. Doctor Light has decided to try his luck with the Flash. His latest invention, the "Photonikron", allows him to cast light illusions around himself, so that he may appear as, literally, anything. At home, Allen is contacted by Dexter Myles, the curator of the Flash Museum. The stolen jewels, from the jewelry store robbery, have appeared at the Flash Museum.
Allen investigates, as the Flash. Observing the gemstones, Myles and the Flash are struck by twin beams of light. Myles is floored, but the Flash only takes a glancing blow. The gemstones, really an illusion-masked Doctor Light, begin peppering the Flash with spheres of light. The Flash retaliates by hammering away at the gemstones. Once again, Doctor Light is on the verge of losing a fight. A blinding potpourri of kaleidoscopic colors explodes around the Flash, giving Doctor Light the chance to change his surrounding illusion. Appearing as Myles, Doctor Light is able to get in a couple of surprise punches, before the Flash mops up the floor with him.
Desperately, Doctor Light, still appearing as Myles, levels one of his special light weapons on the Flash, and murders the Scarlet Speedster. Perceiving no heartbeat, Doctor Light casts the illusion of a concrete slab about the Flash, and carefully places him, on the sidewalk, of a busy Central City street. The Flash, upon recovering, gradually comes to the realization that the world perceives him as a concrete section of sidewalk. After being stepped on a few times too many, the Flash finds that he can still stand up, and does. As he moves down the street, bystanders become terrified at the sight of a mobile block of concrete.
The police take the block into custody, where police scientists attempt to break a piece off the block for analysis. The Flash suffers a pounding chisel blow to his head, being doused in cold water, and scraped on the nose. Finally, the police forensic scientist, desperate to break off a sample of the "concrete block", begins violently kicking the Flash. Having observed the "concrete block" moving down the street, Doctor Light arrives at police headquarters, to finish off the Flash. Vibrating at super-human speed had saved the Flash's life back at the Flash Museum. Now, as those vibrations finally begin to slow, the light illusion fades from around him.
The Flash vibrates into intangibility to avoid Doctor Light's laser attack. Doctor Light counters by switching to a vibratory weapon, attuned to the Flash's very own vibrational wavelength. The Flash blocks and deflects the shot. Doctor Light fills the room with a barrage of light needles. The Flash, vibrating back into intangibility, dives up through the roof to dodge Doctor Light's attack. As the Flash descends back into the room, he blocks Doctor Light's next attack by building up a wall of compressed air in front of him. After mercilessly beating Doctor Light into unconsciousness, the Flash recovers the stolen jewelry. In conversation with Perkins, after returning his jewels to him, the Flash begins to suspect that Perkins is Beth's father. The Flash, and West, reunite Beth with Perkins. To celebrate the happy turn of events, Allen takes West, and Myles, out to dinner.