"Arrow" fans have pretty much been in mourning since Laurel Lance (Katie Cassidy) met her untimely end in Season 4 -- but the 100th episode is about to lift everyone's spirits with a double dose of the fallen Black Canary.

In an alternate reality where Oliver (Stephen Amell) never got on the "Queen's Gambit," never lost his father, and never became the Green Arrow, Laurel is alive and well -- and preparing to marry the love of her life.

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Season 5 has not been short on memories of Laurel and her sacrifice, but the 100th episode manages to honor who she was -- and could have been -- in a powerful, poignant way. According to executive producer Andrew Kreisberg, the decision to include Laurel in such a huge way was a given.

"She is such an essential figure to the show," Kreisberg says, "She was the second lead on the show. Even though the show has evolved, Laurel is at the heart of it. She was Oliver's great love, she's Sarah's sister, she's Lance's daughter... Even if we do get to 200 episodes, Laurel will always be at the heart of the series and be such an important character -- and on top of that, Katie Cassidy will always be so important to us."

Oliver and Laurel's love story never quite took off on "Arrow" like other relationships, but fans of that dynamic will get a peek at what that relationship could have been, had Oliver's life turned out differently.

Before you get your shippers senses tingling however, we'll warn you that this particular episode is light on the romance and heavy on the nostalgia. All of Oliver's relationships -- platonic and otherwise -- are honored in the 100th episode in a very rewarding way.

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Fans will also be treated to some serious sister bonding between Sara (Caity Lotz) and Laurel. We got to see some of the fallout of Laurel's death where Sara was concerned on "Legends of Tomorrow" last season, but in the 100th episode, we get to really dig into how close those two women were. We wouldn't be surprised if one or two tears (as well as a lot of laughs) accompany fans' viewing of their reunion.

And be sure to look out for other familiar faces in the episode -- favorites like Tommy (Colin Donnell) and Roy (Colton Haynes) will make guest appearances, to really drive home the nostalgia factor.

"Arrow" airs Wednesdays at 8 p.m. ET/PT on The CW.

Posted by:Lindsay MacDonald

Lindsay MacDonald is a Los Angeles based entertainment reporter with an affinity for CW superheroes. She graduated from Pepperdine University with a major in Media Studies and a borderline unhealthy obsession with TV in 2012. She would much rather spend the day binge-watching ‘The Flash’ or sorting ‘Game of Thrones’ characters into Hogwarts houses than venturing outdoors. TV words to live by: “Never ignore coincidence. Unless, of course, you’re busy. In which case, always ignore coincidence.”