With the molecules of his legs temporarily merged with those of a brick wall, the Flash is a sitting target for a barrage of missiles. When the smoke clears, the Flash has, seemingly, been obliterated. The Central City Police Department are quick to move in on the Flash's murderer, the Clown. Launched from an ejector seat, the Clown uses his incredible acrobatic prowess to tumble to a rooftop. Instead of fleeing, the Clown doubles back, descending on the officers, riding a rocket-powered flying trapeze. The Clown's shoes begin spraying the officers with a cloying form of cotton candy, which begins to harden and suffocate them.
The Flash, barely on his feet, crawls from the debris, shattered pieces of the wall, protruding from every square inch of his body. Despite the immense pain of moving, the Flash rescues the officers, before racing home. With his wife, Picture News reporter, Iris West, waiting on him, the Flash carefully vibrates, at super-human speed, into intangibility, until he has separated the wall debris from his molecular structure. Frustrated with waiting, West storms out. A mysterious woman removes a piece of the wall debris from the crime scene. By some strange sway she has over the police, not a single officer bars her presence.
The Flash, as police forensics scientist, Barry Allen, is required to attend the first human trial of the Nephron Project. Through aversion therapy, the Nephron Process purports to be able to remove criminal urges from criminals. Convicted murderer, Clive Yorkin, volunteers for the Nephron Process, in exchange for a full pardon, for his crimes, from the governor. Yorkin is strapped into a chair, and forced to watch several criminal acts. As each image appears on the screen before him, Yorkin experiences agonizing pain. Yorkin weathers the ordeal, only to pass out at the first image of non-criminal activity. Allen is dubious regarding the methodology, as well as the ethics, of the Nephron Process.
Meanwhile, the Clown sends a package, to the Flash, by way of police headquarters. As the Clown exits his hotel room, the wind catches the pages of scrapbook. The articles pasted into the scrapbook concern a circus accident, that occurred during a blackout. Three aerialists fell to their deaths, with a fourth severely injured. At the site of a future power plant, the Clown abducts the Governor, the Mayor, and the President of the power company. The package delivered to police headquarters has an article about the Flash's charity appearance at the circus. An appearance the Flash never made, on account of a Justice League of America emergency.
Word reaches the police station regarding the abductions. Allen, as the Flash, scours the city, in search of the Clown, and his victims. The Governor, Mayor, and power company president awaken in chairs, attached to a single wheel, slowly riding across a high tension line. A fourth chair remains empty. The Flash arrives to apprehend the Clown, only to be paralyzed by a single sonic note, played on the Clown's calliope. With the Flash frozen before him, the Clown clubs the Flash into unconsciousness. The Flash awakens in the fourth chair, still largely immobilized. The Clown causes the power lines to sputter and smoke. In a matter of moments, the lines will give, plunging the Clown's victims to their deaths, in a re-enactment of the circus tragedy.... and the Flash can do nothing to prevent it.