'Arrow's' Willa Holland on Thea's 'Dark' Road: This Is the Start of Her Downfall

Executive producer Marc Guggenheim hints that Thea will uncover a "massive" piece of information that "will cause a tectonic shift in her relationship with Oliver."
Cate Cameron/The CW
Willa Holland in "Arrow"

In Starling City, danger is never far and this time Thea is the latest victim.

On Wednesday's Arrow, Slade makes his move against Oliver and the repercussions are big. While Oliver scrambles to protect his family, namely Thea (Willa Holland), whom Slade has in his clutches, a member of Team Arrow starts to doubt Oliver’s decisions.

"Thea learns something pretty massive in episode 18, and it will cause a tectonic shift in her relationship with Oliver," previews Arrow executive producer Marc Guggenheim, hinting that Oliver's sister finds herself in physical and emotional danger.

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"It's a double-edged sword," he adds. "I can guarantee that by the end of [the episode], one of those blades is going to cut her."

"Deathstroke" is the first of many showdowns between nemeses Slade and Oliver and provides "a lot of insight into what's going on in [Slade's] head," Guggenheim says. The episode, which he calls the "mid-midseason finale," offers viewers a better understanding "of Slade's agenda" and "where he's coming from.

"The circumstances are really scary and thrilling, in the sense that Thea has no idea what's happening -- all of a sudden, she gets kidnapped," Holland tells The Hollywood Reporter. "She's not being tortured by Slade physically; he's mentally toying with her and with Oliver. It's an intense episode for Thea, especially toward the end."

When Thea made the ill-timed decision to get into Slade's car at the end of last week's episode, the youngest Queen was left reeling after Roy's abrupt breakup, unaware that her family members were, and are, keeping vital secrets from her -- notably Oliver's superhero life and the identity of her biological father.

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"There's a lot going on in Thea's life that she's aware of and that she's not aware of," Holland says. "This episode and the next few episodes are detrimental for a lot of characters -- they're bringing to light a lot of things that [can destroy] them all. This episode is the start of Thea's somewhat downfall."

The aftereffects of Roy's abrupt breakup will have a major impact on both characters moving forward. "She is the only thing that keeps him in check because she keeps him grounded. If we were going to play Thea in jeopardy, we wanted Roy to feel some sense of complicity in that," Guggenheim says.

Not only that, but the Queen family secret over Thea's biological father, Malcolm Merlyn, will continue to loom large. "The secret that Moira and Oliver have been keeping from Thea will be casting a very long shadow for the rest of the season. It will play a very big role all the way up to the finale," Guggenheim hints.

If and when Thea finds out about her father, Holland posits that things won't be pretty -- rightfully so. She "would handle it the same way most people would handle it -- if you found out something that is detrimental to your livelihood, you would probably freak out a little bit," Holland hypothesizes.

And should Thea uncover Oliver's Arrow identity -- brother and sister already have a "long history of problems with trust" -- their relationship may never be the same again. "She's starting to finally come to a place where she can trust him and he is the only one who she can trust," Holland says, hinting that Thea isn't "too satisfied with her life at the moment."

Coy about the remainder of the sophomore season, the actress teases that the final six episodes bring her character "to a place we definitely did not see coming." Either way, Thea is in for a world of hurt: "Either road she takes, it's pretty dark and dim."

Arrow airs Wednesdays on 8 p.m. on The CW.

Email: Philiana.Ng@THR.com
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