'Arrow': Is Felicity Not Really Dead in the Future?

This week on Arrow, a plot development shed doubt on one of the fundamental beliefs the audience has had about the flash-forward story for most of the season.

Spoilers ahead for tonight's episode of Arrow.

During an exchange with William in 2040, Mia revealed that she does not believe Felicity Smoak is actually dead, and that she is looking to reconnect with her because they "owe each other."

Later, Mia revealed the nature of that relationship: she is in fact Felicity and Oliver's daughter -- although she uses the name "Smoak" and only refers to herself as Felicity's daughter.

The only sign that she is related to Oliver is that she refers to herself as William's sister.

In the final moments of the episode, Felicity got a phone call and seemed very concerned by what she heard. Holding her hand over her abdomen, she looked meaningfully at Oliver. The likelihood is, she is currently pregnant with Mia and just learned it.

Earlier in the season, it was revealed that Felicity went rogue and, acting as the villainous Calculator, got herself in too deep with her criminal cohorts.

If all of this sounds pretty hard to swallow, you are not alone: pretty much nobody seemed to believe Felicity was actually gone-gone, and even money with the fans seems to be that she never went evil at all.

That all seems more likely than ever now.

When we visited the set back in November -- during the production of "Past Sins," stars on the show plead ignorance when asked about Felicity's future fate.

"I actually really can't answer that -- like, I don't know the answer," Juliana Harkavy told reporters last week on set when asked if she believed Felicity was actually dead. "But, I think Felicity has set a path in just the work that she's done, so that leaves a lot of room for us to explore where she's gone on that path."

Harkavy's character got some major story development pertaining to her future self this episode, too: the scar on her throat, seen in the 2040 scenes, was made when she was attacked and slashed by a blade in the hands of Stanley Dover.

Arrow airs on Monday nights at 8 p.m. ET/PT, before episodes of Black Lightning on The CW.