"Unchained" is the 12th episode of the fourth season of the The CW series Arrow and 81st overall. The episode was written by Speed Weed and Beth Schwartz and directed by Kevin Fair. It was first broadcast in February 3, 2016 in The CW. The episode revolves about an attack of a burglar but discover that he is in fact Roy Harper (Colton Haynes), who is being extorted by a man named The Calculator, who is assembling devices to develop a bomb. Meanwhile, Thea continues to fall under the effects of the Lazarus Pit and her bloodlust, but Nyssa may have found an answer for her problem.