'Arrow' season 5 spoilers, news: superhero crossover for show's 100th episode

As the epic superhero crossover continues, "Arrow" celebrates its milestone 100th episode next week.
Titled "Invasion!" next week's episode of "Arrow" will see the next part of the four-way crossover with other superheroes in The CW. According to the official synopsis for episode 8, Oliver (Stephen Amell) suddenly wakes up to a life where he never got on The Queen's Gambit. It will also be revealed that Robert (guest star Jamey Sheridan) and Moira Queen (guest star Susanna Thompson) are alive and well.Laurel (guest star Katie Cassidy) is his loving fiancée and their wedding will soon happen.
Everything seems to be perfect, but Oliver begins to question his new reality when he begins to notice small imperfections that don't make sense. Meanwhile, Felicity (Emily Bett Rickards) and the rest of the recruits must fight against a new threat with the help of Supergirl (guest star Melissa Benoist) and The Flash (guest star Grant Gustin).
The upcoming episode puts the series in an interesting position as it pays tribute to the 99 episodes that came before it. Additionally, it is something special for fans who have been supporting the program since day one. Speaking with Screener, executive producer Wendy Mericle said the crossover was challenging because it fell on the 100th episode, but everyone involved seems confident they've pulled it off.
"We knew that we were going to have to [deal], in some ways, with these new elements that were never in the DNA of the show... Our goal was to do the 100th and make it a love letter very much to that first season -- before there were superpowers, before there were metahumans, before there were aliens, for example," she explained. "I have to say, I think we found this great way of doing it that honors all the other shows, but also is very much an homage our first season and to the Queen family in particular."
"Arrow" season 5 airs Wednesday nights at 8 p.m. ET on The CW.