Crossover: Worlds Finest

Testing his speed, Barry accidentally breaks the barrier between universes and lands in National City, on Kara's Earth, where nobody has heard of the Flash. Supergirl is at a low point: after acting out of control, the city has lost faith in her. Barry becomes an ally; they race and swap hero advice. Silver Banshee and Livewire team up against Kara and go after Cat Grant. With help from the National City fire department, the heroes beat the villains, and the city trusts Supergirl again. To send Barry home, Kara flies with him at top speed and hurls him through the breach. Barry returns to his own Earth, where his own problems are waiting.

1. ReferenceThe name comes from a comic

   "Worlds Finest" nods to World's Finest Comics, the Superman-Batman team-up book where the Flash also showed up often.

   source ↗
2. ReferenceThe Superman #199 race

   The episode's poster mimics the cover of Superman #199 (1967), the first Superman-Flash race. This time it's the cousin racing.

   source ↗
3. Reference"The Blur," like Smallville

   Cat Grant suggests calling the newcomer "The Blur." That was Clark Kent's nickname on Smallville before he became Superman.

   source ↗