'Arrow' season 5 episode 15 spoilers, news: Vigilante targets Mayor Queen; EP reveals future plans for Thea Queen

Vigilante (Mick Wingert) sets his eyes on Mayor Queen (Stephen Arnell) on the upcoming episode of The CW's "Arrow" season 5.

Titled "Fighting Fire with Fire," next week's episode will see Team Arrow come together on a new mission to protect Oliver. According to the official synopsis, Oliver must face his biggest challenge yet as Star City's mayor. While still coping with her boyfriend's death, Felicity (Emily Bett Rickards) continues to embark on her dark path with Helix. After Vigilante targets Oliver while he's still acting mayor, Diggle (David Ramsey) leads the team in a new mission to end Vigilante's reign of terror once and for all.

In the latest episode titled "Specter of the Gun," a member of Oliver's family returned after a long absence: Thea Queen (Willa Holland). She has also only suited up a few times this season because she spent most of her time working in the Mayor's office. However, things will be different in the back half of season 5 as Thea will be getting a lot more to do.

Speaking with Entertainment Weekly, executive producer Wendy Mericle teased that they are working on a bigger story arc for Thea. She also mentioned that there is an upcoming scene featuring the Queen siblings that fans should look forward to.

"She's headed in a direction that's very similar to where her mother was before she was killed in season 2," Mericle said in the media outlet's Spoiler Room segment. "I'm actually really excited about her storyline, because we're taking her to a place where she's been dealing with all of these issues the same way Oliver has, with her bloodlust and with other elements of her past, and this season's going to find her in a similar place, but for very different reasons. There's gonna be a great scene coming up between Oliver and Thea that's one of my favorites on the show," the EP added.

The fifth season of "Arrow" airs every Wednesday night at 8 p.m. ET on The CW.