On Monday's episode of of The CW superhero drama, titled "Spartan," a major setback for Team Arrow -- thanks to the Ninth Circle -- forces Diggle (David Ramsey) to reluctantly reach out to an old friend at the Defense Intelligence Agency, General Stewart (Ernie Hudson), for assistance, though unresolved tension may prove their team-up difficult. Meanwhile, Oliver (Stephen Amell) comes across a key piece of intel that could help turn his half-sister, Emiko (Sea Shimooka), against the evil Ninth Circle once and for all.
In ET's exclusive clip, Oliver and Diggle return to home base with their latest findings in their quest to find Emiko and, as they learn, everyone is working around the clock -- including computer hacker Alena (Kacey Rohl), who's tasked with restoring the security program Archer -- to make sure their newest mission is successful. Team Arrow's desperation in locating Emiko comes with good reason. She doesn't yet know the truth about Dante's (Kirk Acevedo) role in killing her mother, which could very well turn her against the Ninth Circle.
"That would be enough for me to turn myself against the evil organization that raised me as a child," Felicity (Emily Bett Rickards) says, giving her take on the matter. Seconds later, as she tries to hack into Ninth Circle's system, Felicity is thwarted by a security system fail-safe that "fried all the files," installed specifically to prevent someone like her to do what she's trying to do.
But, Felicity reveals that the fail-safe isn't ARGUS code, but written by someone else -- thanks to her extensive hacker knowledge gained from, ahem, past experience. "What would the Ninth Circle want with the Defense Intelligence Agency?" Dinah (Juliana Harkavy) asks. That's where Diggle's past connection to General Stewart comes in.
Arrow executive producers Greg Berlanti and Beth Schwartz told ET in a joint statement: "We’ve had the pleasure of working with Emily since season one and in those past seven years she has brought one of TV’s most beloved characters to life. And although we’re heartbroken to see both Emily and Felicity leave the show, we’re completely supportive of Emily and her future endeavors. She will always have a family at Arrow."
It is unclear how Felicity's storyline will wrap up but the final episodes of the season could offer hints. A flash-forward storyline in the current season revealed Felicity to be alive in the future, operating under the Calculator moniker her father once used. The season also introduced Oliver and Felicity's daughter, Mia Smoak, played by Shadowhunters star Katherine McNamara.