Now that The CW is home to four DC hero primetime shows, the obvious way to celebrate was to do a massive crossover combining the characters of Arrow, The Flash, Legends of Tomorrow, and former CBS property Supergirl. The 3-hour event will include the Girl of Steel, but all the action will take place on the other three shows.
The vigilantes and metahumans will join forces to combat an alien threat known as The Dominators, who plan to invade Earth and harness all of that metahuman energy for their own super-powered army. It's going to be all-hands-on-deck for this epic battle - and for Team Arrow, that could include several surprise arrivals.
This ambitious crossover also coincides with Arrow's 100th episode, and that means plenty of callbacks to the previous four seasons of the show. As actor Stephen Amell recently explained in an interview for Comic Book, those references will begin right at the start of the episode.
"The hundredth episode of Arrow begins in a very appropriate way: it begins with Oliver running. We've had him running into the premiere almost every year, we didn't have him running in this year, but we have him running in the hundredth episode."
Executive producer Marc Guggenheim previously revealed that "Everyone who we could have in the episode, from a scheduling point of view, is in the episode. Even the people who we couldn’t have, because of conflicting schedules, are represented." This reportedly includes Oliver's parents, Black Canary (Katie Cassidy), and Deathstroke (Manu Bennett).
Since the story also includes no flashbacks or Flashpoint timeline, this has raised a lot of questions about how exactly these dearly departed characters will appear. While fans speculate if these reunions occur by time travel, alternate Earth, or dream sequence, Amell would only add that Oliver's family, friends, and enemies would arrive "in a very unexpected spot at a very, very retrospectively expected time."
While that may seem confusingly vague, it does promise that the 100th episode's exciting surprises will not be completely out of left field. Since the Arrowverse has been plagued with some continuity issues in the past, it will be nice if this episode leaves viewers with a feeling that all the pieces have finally fallen into place. It'll be an even bigger bonus if these revivals lead to a permanent return for at least a few of the more intriguing characters.
Supergirl season 2 airs Mondays at 8pm on The CW; The Flash season 3 airs Tuesdays in the same timeslot; Arrow season 5 airs on Wednesdays; and Legends of Tomorrow season 2 airs on Thursdays.
Source: Comic Book