The Reverse Flash teams up with Mr. Element.

Police Forensics Scientist, Barry Allen, and his girlfriend, Picture News Reporter, Iris West, are meeting Al Desmond, and his fiancee, Rita, for dinner. Desmond once terrorized Central City as both the villainous Mr. Element, as well as the nefarious Doctor Alchemy. Having paid his debt to society, Desmond has reformed. At dinner, Desmond complains of a sudden headache, and departs for home. Trancelike, he finds himself, instead, returning to his criminal lair. Uncovering his old laboratory equipment, Desmond mixes up a batch of chemicals, with volatile results. As the smoke clears, Desmond finds himself facing Professor Zoom, the Reverse Flash. Having taken control of Desmond's mind, Professor Zoom telepathically explains his presence in the 20th century.

After losing the Flash costume that gave him his incredible super-speed, Professor Zoom became obsessed with regaining his powers. Professor Zoom discovered an element, that he dubbed "Element Z", that gave him super-human speed. Element Z, however, proved to be too unstable to maintain his powers for more than a few moments. Searching the history books, Professor Zoom learned that Desmond is the only chemist brilliant enough to stabilize Element Z. Desmond, though, refuses. His brilliance is too tied to the criminal side of his mind. Undeterred, Professor Zoom telepathically forces Desmond to don his Mr. Element costume, and to resume his criminal career. Desmond, as Mr. Element, strikes at the Egyptian Museum, intent on stealing the Horus Scarab.

After taking out the guards with a block of pure sodium, Mr. Element reaches for the Horus Scarab, but finds he cannot take it. The Flash arrives on the scene, crestfallen to discover that Desmond has resumed his criminal career. Mr. Element stops the Flash with a web of crystal iron, which impedes the Scarlet Speedster's forward motion, before snapping him back, hard, into the wall. When the Flash revives, Mr. Element is gone, but the Horus Scarab remains. Mr. Element returns to Professor Zoom empty-handed. Professor Zoom doubles his efforts to return Mr. Element to his criminal ways. Mr. Element is commanded to rob the Federal Treasury building. Mr. Element uses heated zirconium to literally burn through the brick walls of the treasury building.

This time, Mr. Element does take the loot, but, still resisting Professor Zoom's mind control, he walks very slowly back to the hideout. The Flash closes in on Mr. Element, at the exact same moment that Professor Zoom is racing to his aid. The two super-speedsters violently collide with one another. Professor Zoom recovers first, and lays the Flash out with a telepathic force blast. Resigned to the fact that Professor Zoom has once more made him a criminal, Mr. Element sets about to stabilizing Element Z. As Professor Zoom had hoped, Mr. Element is successful in purifying and stabilizing Element Z. Wearing Element Z in a necklace around his neck, Professor Zoom is thrilled to regain his super-speed powers.

Having gotten what he wanted, Professor Zoom takes his leave of Mr. Element. Following the residual trail the Flash leaves, when moving at super-speed, Professor Zoom tracks down the Flash's Cosmic Treadmill, to return to his era. The Flash arrives just as Professor Zoom fades away. Without wasting a moment, the Flash pursues Professor Zoom, into the future. Professor Zoom issues the government an ultimatum, to pay him a billion in credits, lest he uses his powers to release every single criminal from the world's prisons. To prove his threat, Professor Zoom releases an old convict buddy, Foxy. Learning of Professor Zoom's scheme, the Flash begins patrolling prisons, until he encounters his adversary.

An epic battle ensues, with each combatant moving at incredible velocity. Ultimately, the Flash's greater super-speed experience wins the day. With the Element Z removed from Professor Zoom's necklace, the Reverse Flash finds himself without powers anew. After Professor Zoom has been incarcerated, the Flash returns to his proper era, The Flash learns that Mr. Element returned all of the stolen money. Once the Flash has revealed that Mr. Element was the helpless victim of Professor Zoom, criminal charges are dropped. Allen and West join Desmond, and his fiancee, again, for dinner. Desmond voices his fears of having another "headache". With Professor Zoom safely behind bars in the 25th Century, Allen knows those fears are groundless.

Notes:

• The cover is a homage to the cover of The Flash #123.

• This comic book appeared in the movie Catch Me if You Can.