The next episode of "Arrow" season 4, which is titled "Unchained," will be extra electrifying because viewers will see a much-loved familiar face once again while a new dreadful opponent strives to cast his shadow on Star City.

Actor Colton Haynes suits up once more as Roy Harper a.k.a. Arsenal. The red-clad hero has found his way to Team Arrow again for an agenda that still remains unclear.

The "Arrow" season 4 episode will likely see Roy in action but it seems that the feeling of getting back out there fighting bad guys on the field is not the only thing he came for. What brought him back in town should be revealed by the end of the hour.

Interestingly, the bunch of promotional images shows no sign of Thea, who is definitely a big of a deal to Roy enough to lure him back to the city. Speedy seems to have come across some kind of trouble in this episode.

Roy's arrival is also in perfect timing because Team Arrow could really use some help. A new villain who goes by the name The Calculator is doing some damage in the city. The promo for the "Arrow" season 4 episode hints that he may be as tech-savvy as Felicity.

The clip also teases that what The Calculator has concocted can kill everyone in the city, so Oliver and the group are racing against the clock to stop this one massive explosion before it turns the city to dust.

The promotional images for the "Arrow" season 4 episode also show that apart from The Calculator, the team will be dealing with Damien Darhk's mega-evil wife. The synopsis also hints that apart from Roy, Nyssa will also make an appearance.

"Arrow" season 4 episode 12 "Unchained" airs Feb. 3 at 8pm ET on CW.