The most important thing coming out of this crossover is that Supergirl is truly now part of the DC TV universe.
Everyone who we could have in the episode from a scheduling point of view is in the episode.
Arrow‘s episode of the crossover also just so happens to be the series’ 100th, which means it had its own requirements to commemorate this big milestone.
begins Monday, Nov. 28 with Supergirl at 8 p.m. EST on The CW, and continues with The Flash at the same time on Tuesday, Arrow on Wednesday, and Legends of Tomorrow on Thursday.