Kara gains a new ally when the lightning-fast superhero The Flash suddenly appears from an alternate universe and helps Kara battle Siobhan, aka Silver Banshee, and Livewire in exchange for her help in finding a way to return him home.
Behind the scenes
- The episode's title is a reference to the World's Finest comics, which would have Superman and Batman crossover.
- However, since the Flash and Supergirl come from different worlds, the title is spelled with plural, rather than possessive.
- The promotional poster released for the episode is a reference to the cover of Superman #199, in which The Flash crossed over to verse Superman.
- Winn refers to himself and Barry as the "dynamic duo", a moniker frequently used to describe Batman and Robin.
- Cat refers to James, Barry, Winn and Kara as the "the attractive yet non-threatening, racially diverse cast of a CW show". This is a reference to traits frequently noted by media regarding The Flash.
- Barry references a number of existing alternate universes. He mentions a world where the Nazis won WWII and a world where everyone is evil versions of themselves. He mentions having been to the latter, presumably referring to Earth Two, on which Caitlin, Ronnie and Cisco's doppelgängers are all villains.
- Cat decides to nickname The Flash "The Blur", referencing a name given to Clark Kent on Smallville.
- Siobhan's aunt, Sinead, refers to her customers as "Muggles", referencing a term frequently used in the Harry Potter series.
- Lucy Lane suggests calling the Flash "Speedy", referencing Thea Queen's alter ego.
- Cat tells Livewire and Silver Banshee, both her former employees, that they should call "Norma Rae" and ask her how it's done. This is a reference to the film of the same name where Sally Field played a union organizer.
- Kara tells James that she wanted to discuss "infinite Earths". This phrasing is a reference to the DC Comics storyline Crisis on Infinite Earths.
|Supergirl season 1|
|"Pilot" • "Stronger Together" • "Fight or Flight" • "Livewire" • "How Does She Do It?" • "Red Faced" • "Human For a Day" • "Hostile Takeover" • "Blood Bonds" • "Childish Things" • "Strange Visitor From Another Planet" • "Bizarro" • "For the Girl Who Has Everything" • "Truth, Justice and the American Way" • "Solitude" • "Falling" • "Manhunter" • "Worlds Finest" • "Myriad" • "Better Angels"|