Barry asks Green Arrow for help when aliens attack Central City, but when they realize that won't be enough, they bring the Legends and Supergirl in on the battle.
Of the several characters assembled at the de facto "Hall of Justice" during the crossover, Barry Allen (Flash), Oliver Queen (Green Arrow), Cisco Ramon (Vibe), Wally West (Kid Flash), Kara Danvers (Supergirl), Professor Stein (half of Firestorm) and Ray Palmer (Atom) were actually members of the Justice League in the comic books. The others are either non-members or replacement characters created for the series.
Green Arrow:
Oh, wow! You really did it this time, Barry.
The Flash:
Seriously?
Green Arrow:
Yeah, yeah. Yeah, seriously! You to come to Star City, ask for my help, and then, inevitably, immediately, we end up the creek!
When Barry introduces Supergirl and she levitates to prove her alien nature, she also uses her heat vision to burn her family crest into the floor behind the rest of the team. No one looks at what she's doing, only looking at her, which they should as, from their positions, her heat vision would have had to cut through Professor Stein. The heat-vision effect was added in post and not originally scripted. Later in story-time, Barry has to explain Kara's heat vision to Oliver quickly in battle, which he should know from the aforementioned introduction. Complicated by that explanation being depicted twice.
To be continued on Arrow (2012)
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