The crossover event will pit the CW heroes against The Dominators, a group of technologically advanced alien species dedicated to eliminating the threat of metahumans, prompting our heroes to bring in an alien ally of their own. Guggenheim explains:
“Once the heroes realize that they’re up against aliens, they decide that they need an alien on their side. Fortunately, Barry knows a really nice one. I don’t think it’s a big shock that between Barry and Cisco, and all their experiences with Earth-2 and the multi-verse, that they can pluck her from Earth-CBS.”
While the crossover is being touted as four-part event, Guggenheim considers it to be more of a three-part event, with Supergirl kicking off the story when Cisco and Barry appear to enlist Kara’s help at the end of a Supergirl episode.
“Some people call it a four-way crossover because it involves four shows; my ulcer requires me to call it a three-part crossover. The story that’s being told has a beginning, middle, and end: a beginning inFlash, a middle in Arrow, and an end in Legends. But Supergirl is very much a part of the whole thing, so we are crossing over four shows — four shows in three parts.”
Guggenheim elaborated, explaining that in addition to John Barrowman and Neal McDonough reprising their respective roles as Malcolm Merlyn and Damien Darhk, the 100th episode will pay tribute to the shows history.
“I haven’t seen the episode all cut together yet, but it has some incredibly iconic moments. It is a love letter to the show, it draws on all previous 99 episodes pretty much. 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. At the same time, you’ve got Flash and Supergirl; that’s an enormous amount of fun. Certainly the recruits also play a very large role, an important role, in the episode. I’m really excited about it.”
Guggenheim also stated that the 100th episode of Arrow will feature series star Stephen Amell’s greatest performance yet as Oliver Queen.
“There’s one moment in it that I think is probably Stephen’s finest performance to date. This one scene, that really has two moments within the one scene, it will break your heart. It will take your heart, pull it out, and stomp it on the floor. It’s very, very affecting. It’s all on Stephen’s back. It’s incredible. Willa [Holland]’s amazing in the episode. Everyone obviously brought their A game to it. I’m really, really excited about it. It’s the 100th episode!”
