Following last night's shocking finale, "Arrow" will pit the heroes of Starling City against a new villain: the Calculator. The name's not that intimidating, and Felicity says as much in the trailer for "Unchained," but the Calculator looks to have the upper hand in the CW's promo.

"Arrow" Recap: Felicity Gets a Code Name, Andy and Diggle Protect A.R.G.U.S.

The episode will also see the return of Colton Haynes as Roy Harper, although the former series regular is nowhere to be seen in the clip. Instead, the trailer focuses squarely on Felicity (Emily Bett Rickards), a fitting choice considering that the character finally received a codename in last night's ep.

ROY HARPER RETURNS; NYSSA MAKES HER MOVE -- 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. Kevin Fair directed the episode written by Speed Weed & Beth Schwartz (#412). Original airdate 2/3/2016.

"Arrow" airs on Wednesdays on the CW.