Executive Producer Marc Guggenheim has revealed that Supergirl's (Melissa Benoist) new presence in the CW's DC Universe will heavily factor in to the networks four-show crossover event...
When Supergirl was announced to be moving to the CW for its second season, it was followed up by the news that all four shows would be a part of a mega-crossover event during the upcoming fall season. While details are still scarce on how Kara will arrive on the new earth from her current one, executive producer Marc Guggenheim (speaking at Comic-Con) revealed that her presence, along with a new threat, is what will instigate the events of the episodes. "It’s an external threat from outside the shows that will involve Supergirl coming over to The Flash, then Arrow then Legends of Tomorrow."