"Worlds Finest" is the eighteenth episode of the first season of Supergirl, and the eighteenth episode overall. It aired on March 28, 2016. It acts as a crossover between Supergirl and The Flash.


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.[1]


  • This episode marks the first time that a main cast member was not present for the episode. The cast members not present were Chyler Leigh (Alex Danvers) and David Harewood (J'onn J'onzz). This leaves only four cast members to appear in every episode: Melissa Benoist (Kara Danvers), Jeremy Jordan (Winn Schott), Calista Flockhart (Cat Grant), and Mehcad Brooks (James Olsen).
  • 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.


Promotional images



  1. ‘Supergirl’ & ‘The Flash’ Reveal Key Art & Crossover Plot For ‘World’s Finest’ - Deadline