A comet strikes the sun, endangering Earth-2 with radiation. Meanwhile, Barry and Iris attend a costume party on Earth 1, and the proceeds are stolen by Captain Cold. Two crimes, two Flashes! Jay Garrick and Barry Allen once again join forces as the Flash of Two Worlds!
A comet strikes the sun, touching off a solar flare of deadly epsilon radiation. The entire populace of Earth is in danger of being wiped out by the radiation. A meteorite is discovered in Arizona that can absorb the fatal radiation. Jay Garrick is tasked, by the President of The United States, to find a way to use the meteor to absorb all the radiation. When Garrick arrives in Arizona, though, he can find no trace of the meteor. Garrick, as the Golden Age Flash, travels to Earth-1, in the hopes of finding a similar meteor, on the parallel world. Police forensic scientist, Barry Allen, and Picture News reporter, Iris West, are attending a costumed Headline Makers Ball. Allen sees several party guests dressed in the costumes of notorious criminals, like the Mirror Master and the Top.
Two such "guests" truly are Captain Cold and the Trickster. Captain Cold is in the process of looting the charity receipts, when the Trickster interrupts and takes the money for himself. The Trickster is quick to disable Captain Cold's gun. Recognizing a robbery when he sees one, the Golden Age Flash intervenes, preventing the Trickster from escaping. Unjamming his weapon, Captain Cold lays an ice sheath across the floor. The Golden Age Flash skids into a wall, knocking himself out. Proving there's no honor among thieves, the Trickster flies off with the loot, leaving Captain Cold behind. Learning of the robbery, Allen investigates, as the Flash. Encountering his counterpart, the Flash is brought up to speed on the situation.
The two Flashes take off in pursuit of the fleeing felons. The Flashes find Captain Cold and the Trickster fighting over the stolen money. Captain Cold quickly freezes the Flash. The Golden Age Flash closes in on Captain Cold, only to be hooked by the Trickster. With the Trickster holding the Golden Age Flash in the air, Captain Cold is able to easily freeze him, as well. Acknowledging how well they work together, Captain Cold and the Trickster form a partnership. Vibrating at super-human speed, the Flashes shatter their icy encasements. While the Golden Age Flash gets on with his mission to collect the meteor, the Silver Age Flash pursues Captain Cold and the Trickster. The Golden Age Flash finds that the meteor on Earth-1 is much larger, and still buried.
The Golden Age Flash excavates the meteor, then breaks it up into smaller pieces. The Golden Age Flash has the meteor fragments flown back to Central City. There, he and the Silver Age Flash build a vibratory transport that will teleport the meteor fragments to Earth-2. Thanks to a story planted in the latest edition of Picture News, Captain Cold and the Trickster are led to believe the meteor fragments are valuable. The two costumed crooks show up to steal it, falling into the Flashes' trap. It's all the two felons can do to escape. The Golden Age Flash goes after the Trickster, and brings him down to Earth with a super-speed generated wind column. The Trickster, though, turns out to be one of Captain Cold's mirages.
Anticipating that tactic, the Silver Age Flash stayed on Captain Cold's trail, while leaving a path for the Golden Age Flash to follow. The Silver Age Flash confronts Captain Cold and the Trickster in their hideout. While their attention is on their old foe, the Golden Age Flash, moving so fast as to be invisible, grabs their hands and turns their weapons on themselves. The meteor fragments absorb all the deadly epsilon radiation threatening Earth-2, saving all life on Earth. Knowing that events that occur on Earth-2 also happen on Earth-1, the Golden Age Flash uses his background in chemistry to synthesize the meteor metal, for use on Earth-1, should that world be similarly imperiled.