Three Ghosts

"Three Ghosts" is the ninth episode of the second season of Arrow, mid-season finale, and thirty-second episode overall. It aired on December 11, 2013.

Synopsis
After a fight with Cyrus Gold AKA the Acolyte, Oliver is drugged and left for dead. Determined to cure him, Felicity makes a risky decision. The cure causes Oliver to hallucinate, and what he sees forces him to confront his past. Meanwhile, Barry continues to help Felicity, and their connection grows stronger. The Arrow asks Lance to look into Gold, but when the stakeout on Gold goes bad, someone gets killed. Roy is captured and tortured by Brother Blood.

Plot
Barry manages to save Oliver's life, but Oliver is angry to find out that Felicity has revealed his secret when he regains consciousness. Back at Queen's house Thea revealed Roy did not go to the hospital and needed aid, Oliver took out the arrow and called for John to come over with First Aid kit. Oliver starts to hallucinate, as well as a flash back with Slade dying, Oliver, Shado, Sara being held at gunpoint and led outside the sub. Oliver went back to the Arrow's hideout, and asked about side effects from Barry. Barry and Felicity are able to identify and locate Oliver's attacker, Cyrus Gold. While continuing to discover the truth behind the death of Sin's friend Max, Roy is captured by Cyrus and brought before Sebastian who injects him with the Mirakuru serum. The serum fails to work and kills Roy. Oliver arrives but defeated by Cyrus, had another hallucination about Tommy. Tommy encourages him to keep on fighting and stop Cyrus, he then destroys the remaining serum. Oliver revives Roy, but later worries that the serum may affect him negatively. It is revealed the mastermind of this is Slade (alive and all), he states that new Mirakuru can be made with his blood and he will corrupt or kill "The hood's" followers or the ones he loved before killing him himself because just killing him is too easy for him. Ordering Blood to leave the vigilante alone for his plans. In flashbacks, Ivo kills Shado, but flees when Slade turns up with super-human strength and kills his men. Oliver went back to the hideout. Barry leaves a green domino mask for Oliver, to better hide his identity, and returns to Central City. A malfunction with the new particle accelerator, coupled with a lightning storm, causes an explosion and Barry is caught in the blast. Felicity helps Oliver puts on his new mask.

Trivia

 * The three "ghosts" who appear to Oliver are a reference Charles Dickens' A Christmas Carol. In following this, Shado is that of the past, with Slade representing Oliver's current self doubts, and Tommy finally offering redemption and a future for Oliver.
 * Slade in the present day has an eye patch and his hair appears to be greying, both elements which are usually present on Slade's character.
 * Reporter "Linda Park" is a reference to Wally West's (The Third Flash) wife.
 * In one of the relatively few direct references to her Judaism, when Barry asks what Felicity will be doing for Christmas she replies, "Lighting my menorah.".
 * This episode talks about the English nursery rhyme, "Solomon Grundy", stating that it's about the seven stages of life.

Production
Preparation ran from October 1 until October 9, 2013. Shooting ran from October 10 until October 22, 2013.