Team Arrow will work together to try to stop a new villain named "The Calculator" from destroying Star City in the next episode of "Arrow."

A synopsis for the upcoming installment, which is titled "Unchained," reveals that Colton Haynes will reprise his role as Roy Harper, while viewers will meet The Calculator. Katrina Law will also return as Nyssa al Ghul.

"The team faces off against a formidable villain nicknamed The Calculator (guest star Tom Amandes). Meanwhile, Nyssa (guest star Katrina Law) makes her move and Roy Harper (guest star Colton Haynes) returns to Star City," states the synopsis, according to Carter Matt.

The trailer video, however, does not give fans a glimpse of Roy or Nyssa. Instead, it focuses on Felicity Smoak (Emily Bett Rickards) facing off with the new villain.

During an interview with TVLine, executive producer Wendy Mericle opened up about Roy's return to Star City and how that storyline will tie in with The Calculator, a DC Comic villain. According to the EP, Amandes will make his first appearance as Noah Kuttler, a criminal mastermind and technical genius who uses his advanced skills in computer scions and Internet manipulation to blackmail Roy out of retirement to do his bidding. As a result, Roy will end up on Team Arrow's radar.

"Roy comes back in a really surprising, new way. Like Oliver, he seems to have fallen back into some old habits," Mericle teased.

In addition, the EP revealed that Amandes' character will "have a connection to Felicity," reports EW.

In the last episode, "Arrow's" favorite IT girl finally got her own cool codename, which is "Overwatch," the name of "Arrow" executive producer Marc Guggenheim's CIA conspiracy novel, reports Entertainment Weekly.

Season 4, Episode 12 of "Arrow," titled "Unchained," will air on Wednesday, Feb. 3 at 8 p.m. ET on The CW.

Watch a preview video below: