The Reverse-Flash impersonates Barry Allen with the intent of marrying Iris West!
Nighttime in Central City finds the Flash taking down a trio of would-be bank robbers. The Flash's mind, however, is preoccupied with whether or not to reveal his secret identity, to Picture News reporter, Iris West, prior to their wedding. The next morning, the wedding guests assemble at the church. On hand to celebrate the momentous occasion are the bride's father, Professor West, Wally West, and his parents, the curator of the Flash Museum, Dexter Myles, actress Daphne Dean, Al and Rita Desmond, and the groom's parents, Doctor and Mrs. Allen.
West is escorted down the aisle, to stand beside her would-be husband, police forensics scientist, Barry Allen. Just before the minister can complete the ceremony, the Flash barges in and accuses Allen of being an imposter. Flashback, and forward, to the 25th Century, where the Flash's nemesis, Professor Zoom stands incarcerated. The Reverse Flash telepathically switches minds, and body, with Allen, taking his place in the 20th Century. Using a matter distributer, Professor Zoom alters his face to look like Allen's. Intending to take the Flash's place, in every possible way, Professor Zoom, as the Flash, responds to a police bulletin about a robbery.
Professor Zoom uses the matter distributer to subdue the would-be jewel thieves. However, when Professor Zoom moves to return the stolen diamonds, he finds he just can't do it. Instead, Professor Zoom keeps the diamonds himself. Racing around the city as the Flash, Professor Zoom revels in the newfound respect and admiration he receives from Central City's populace. Meanwhile, Allen finds himself trapped in Professor Zoom's cell, in the 25th Century. Realizing his super-speed abilities will avail him naught in escaping, Allen, instead, uses the powerful suction of his Flash costume ring, to weaken the radioactive walls of this cell.
The Flash is finally able to pull himself out of the cell, overpower the guards, and return to the 20th Century, just in time to stop the wedding. The Flash grabs "Allen", and whisks him out of the chapel, to the astonished eyes of the wedding party. Donning his Reverse Flash costume, Professor Zoom agrees to fight the Flash for the honor of marrying West. The two super-speedsters engage in an epic battle, that spans all of Central City. Having not completely mastered all of the Flash's super-speed tricks, Professor Zoom fails to run across the surface of a nearby lake, allowing the Flash to gain the advantage over him.
With Professor Zoom unconscious, authorities from the 25th Century take possession of the Reverse Flash, promising to do a better job of keeping him incarcerated. The Flash, as Allen, returns to the chapel, and marries West. With Wally West, as Kid Flash, keeping a watchful eye over Central City, the happy couple depart on their honeymoon. Allen continues to wrestle with the question of whether or not to reveal his secret identity to West.