Roy Harper returns in the next episode of "Arrow" season 4.

Colton Haynes' character was last seen in the series when he faked his own death to protect the secret identity of the Green Arrow (Stephen Amell). But his return to Star City will also mean that his alter ego Arsenal will appear as well.

The CW released the official synopsis for the episode titled "Unchained," which reads:

"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."

Roy's return to Star City could possibly have a huge impact on Thea (Willa Holland), who was deeply affected when he disappeared. But since Thea has already moved on, it would be interesting to see how she will react when she encounters Roy again face to face in the upcoming episode.

According to Design & Trend, Thea will be rattled for a short while upon seeing Roy again, but her feelings will not be a hindrance to her crime-fighting tasks with the rest of Team Arrow. However, a love triangle might erupt between Thea, Roy, and Thea's new love interest Alex Davis (Parker Young) in the coming installment of the series.

Meanwhile, the upcoming episode will also feature Felicity's (Emily Bett Rickards) struggles as she adjusts to her new life in a wheelchair. Things will be hard for her, but the rest of the Team Arrow, particularly Oliver (Amell), John Diggle (David Ramsey), Thea, and Roy will help her. They also need her help to be able to defeat The Calculator as he also has the same computer skills that Felicity has.

Damien Darhk's (Neal McDonough)'s wife Nyssa will also show what she is capable of in the upcoming episode.

"Arrow" season 4 episode 12 airs on Wednesday, Feb. 3, on The CW.