2.09: “Three Ghosts”
Oliver is dying from being injected with a ragged form of the Mirakuru serum. In his second appearance in the Arrowverse, Central City CSI Barry Allen is able to save Oliver’s life with rat poison, but it has the side effect of hallucinations that appear to Oliver like the three ghosts in Dickens’ A Christmas Carol. Oliver is furious that his secret was revealed without his permission. Barry offers to help identify Oliver’s attacker. Roy investigates a psychiatric firm who gave donors at a blood drive psych evaluations and gets captured by Cyrus Gold, a violent henchman of Sebastian Blood, mayoral candidate and secret cult leader. Barry tracks Gold down to a lab and Oliver goes after him. Blood, in mask, and Gold have Roy tied up and injected with Mirakuru. Oliver breaks in, eventually takes down Gold and frees Roy, who he now must keep an eye on. In the past, Ivo gives Oliver a choice between killing Shado or Sara. When he steps in front of the gun to protect Sara, Ivo shoots Shado. Slade springs to life, his injuries healed. He runs to help Shado and finds her dead, setting off the massive chain of events that fuels the season.
2.15: “The Promise”
Oliver is shocked to see Slade Wilson alive and in the Queen home, talking to Moira about her campaign. He can’t do anything to Slade with Moira and Thea there, but treats Slade with open disdain, much to Moira’s chagrin. Slade has the women give him a tour of the artwork of the house, cover to hide a number of cameras and listening devices. Altered to the threat, Sara, Roy, and Diggle intervene. With the evening over, as Oliver walks him to his car, Slade reminds him of a promise he made on the island. In the past, Oliver, Slade, and Sara attack the Amazo, freeing prisoners. When Oliver confronts Ivo, Slade overhears that it was Oliver’s decision that cost Shado her life. He turns on Oliver, capturing Ivo and Oliver, making a promise that he won’t kill Oliver until his life is put through utter despair.
2.16: “Suicide Squad”
Diggle-centric episodes are a personal fave. He gets pulled by Waller into working with a group of criminals formed into a special ops force for ARGUS. The group — Diggle, Lyla, Bronze Tiger, Shrapnel, and Deadshot — targets a terrorist, who Diggle onced saved while on tour in Afghanistan, planning to use a neurotoxin. They discover the cache of neurotoxin is too large and that Waller had planned to use drones targeting killswitches implanted in each of the criminal’s heads to blow up the facility; essentially a suicide mission. Diggle and Lyla change the play, taking out the target and getting the squad to safety. Shrapnel is all but wasted in story to demonstrate the killswitch, but there’s a lot of fun to be had with this group having to work together, specifically Diggle and Deadshot.
Slade is done waiting and puts his plans against Oliver into action. He abducts Thea but uses it to tell her that Malcolm is her father and Oliver knew, driving a wedge between them. As Oliver searches for Thea, Slade uses the distraction to free a bus full of hardened inmates, planning to turn the into Mirakuru soldiers. Oliver discovers that Isabel has been working for Slade from the beginning, and he begins to realize just how much Slade’s machinations are insinuated into his life the last few months.
2.19: “The Man Under the Hood”
Team Arrow blows up Queen Consolidated Applied Sciences to prevent Slade from making the Mirakuru. Slade steals a device used by another featured baddie, the Clock King, to break into a S.T.A.R. Labs facility for a specialized blood transfusion device. Felicity traces the device when it goes active, and Oliver discovers that it is none other than Roy Harper being used to create Mirakuru serum from his blood. Oliver fights Slade and Isabel to free Roy. Diggle shoots and kills Isabel, but Slade is able to use his blood to revive her. Roy is left in a coma. Oliver and Sara believe that Professor Ivo was developing a cure in the past and want to test it on Roy. Felicity extracts Mirakuru from Roy’s blood and turns it over to The Flash‘s Caitlin Snow and Cisco Ramon with S.T.A.R. Labs (pre-Flash) to synthesize the potential cure. Now knowing that Oliver is the Arrow, Laurel realizes that her sister is the Canary.
2.20: “Seeing Red”
Rescued from being the source of Slade’s Mirakuru blood to turn soldiers, Roy awakes from a coma enraged. He goes hunting for Thea, and Team Arrow attempts to stop him. He hurts Oliver and kills a cop in his rage, and Sara is convinced to have to kill him. Oliver convinces her otherwise. Thea learns what happened to Roy from Sin and uses Moira’s mayoral press rally to lure Roy out. Roy goes to Verdant to see Thea, and Oliver and Sara are able to subdue him with snake venom poison. Moira wins the election and reveals to Oliver she knows he is the Arrow. As Thea joins her mother and brother in the car to talk about repairing things, they are attacked by Slade. He gives Oliver the same option as the island, but this time choosing between Moira and Thea. Moira sacrifices herself to the horror of Oliver and Thea. In the past, Moira learns Oliver got a girl pregnant and takes care of it.
2.22: “Streets of Fire”
Oliver and Laurel survive the blast underground and get free, as Diggle and Felicity fight Isabel with a van. The group meets up and learns that S.T.A.R. Labs has finished the Mirakuru cure and is rushing it into the city. Slade’s soldiers get to cure before Team Arrow can. Laurel runs into Canary and reveals she knows she’s her sister. Sara is still struggling with being a hero, but Laurel offers her encouragement. Sara saves a young girl from a house fire, and Laurel publicly calls her the Canary for the first time, the name taken from Sara’s Arabic moniker. Laurel joins her dad at the police station. The officers follow Quentin’s lead in helping the Arrow fight for the city and he’s promoted back to Detective. Sebastian is devastated at Slade’s true plans to demolish the city and steals the cure to give to Oliver. Isabel kills him for his betrayal. They test the cure on Roy, as ARGUS begins to block off the city. Oliver calls Waller and she reveals that she’s put a clock on the situation, intending to destroy the city with drones to prevent the Mirakuru from spreading anywhere else. Thea is attacked by a soldier while trying to leave town, and is saved by Malcolm.
Fans and we agree that this was the best episode of the season. It might possibly be the best episode of the series to date. Slade’s final move is to kill the one whom Oliver loves the most. With the Mirakuru soldiers attacking the city, ARGUS ready to strike, and a working cure, Team Arrow, Lyla, Canary, Nyssa, and League assassins set out to take down the soldiers non-lethally. They make way to Slade at the QC building, but he escapes. Nyssa kills Isabel. Laurel is abducted, and when Quentin arrives to tell the Arrow, he insists he start killing again. Felicity convinces Oliver he needs to do something unthinkable, and Oliver devices a gameplan that Slade would never anticipate he would do. Taking Felicity to the mansion, Oliver confesses his love for her, knowing that Slade has the place bugged. Felicity is nabbed once Oliver leaves, and both Laurel and Felicity are brought to the final confrontation with Slade, as Waller’s drones descend on the city. The confession was a ruse, as Oliver slipped Felicity an arrowhead with the cure so that she could get close to Slade. She injects him and the effects of the Mirakuru are counteracted. Oliver and Slade have a final fight, as Diggle and Lyla break the Suicide Squad out of prison to fight their way to Waller to stop her. They convince her to call off the strike. Oliver bests Slade but doesn’t kill him. Slade is placed in an ARGUS supermax prison underground on Lian Yu, of all places. Oliver and company prepare to rebuild. After what she feels is a final betrayal by Roy, Thea joins her father, Malcolm Merlyn, and they leave the city. In the past, Oliver attempts to rescue Sara and faces Slade, seemingly for the last time. Anatoli fires on freighter with the submarine, per Oliver’s orders. As the boat sinks, Sara is swept out to sea, lost again. Oliver and Slade viciously battle, with Oliver finally getting the upper hand and stabbing Slade through the eye, seemingly killing him. Oliver nearly drowns. He wakes on the mainland in Hong Kong and is introduced for the first time to Amanda Waller.