Watch Arrow season 4 episode 12 online The CW

Arrow season 4 returns with episode 12 titled Unchained. Lots of exciting stuff happening on this upcoming episode — Roy Harper and Nyssa al Ghul return and Team Arrow face a new villain who might just have a pretty shocking connection to Felicity.

"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," reads the official synopsis for Unchained.

Talking about Roy Harper's return to Arrow, Felicity actress Emily Bett Rickards, told Emertainment Monthly that she would want the character to feature in every episode of Arrow! "I hope Roy comes back every episode of every season for all seasons of Arrow. I love having him back and he is my absolutely favorite human being and I'm not afraid to admit it. His episode is SO killer! It's SO good!"

Meanwhile, TV Guide reports that the Calculator is described as being a bit of a super-genius that's capable of throwing Team Arrow through a loop, particularly its shakiest member right now, Felicity. According to Entertainment Weekly, fans believe that the new deadly villain may turn out to be the newly code-named Overwatch's long-lost father.

Arrow season 4 episode 12 airs this Wednesday, 3 February at 8pm EST. You can click here to watch the episode online.