02x01 - City of Heroes Diggle and Felicity travel to Lian Yu in search of Oliver who left Starling City after The Undertaking. Convinced to return home, Oliver finds that things are in worse shape than he thought - Isabel Rochev is preparing a hostile takeover of Queen Consolidated, Thea refuses to visit Moira in jail, Roy is trying to fill the void left by the Arrow's absence, and Laurel is working with the District Attorney's office to take down the vigilante. Meanwhile, flashbacks to the island show Slade, Shado, and Oliver in a desperate situation. 02x02 - Identity Oliver finds out the medicine that is being sent to Glades Memorial is being hijacked by thieves. Without an influx of supplies, the hospital will close. Roy attempts to stop the thieves, but he fails and is arrested by Officer Lance. Oliver gets into a heated battle with China White and her new partner, Ben Turner, AKA the Bronze Tiger, over the supplies. Meanwhile, Laurel makes plans to catch the Arrow, and Thea gives Roy an ultimatum. 02x03 - Broken Dolls Lance learns a criminal named Barton Mathis, whom he put away years ago, broke out of prison during the quake and is back to torturing and murdering women. Felicity offers herself as bait so Arrow, Diggle, and Lance can catch this villain, but the plan goes awry. Furious, Mathis kidnaps Laurel in retaliation and plans to murder her while Lance watches. Meanwhile, Thea and Oliver are stunned when District Attorney Adam Donner seeks the death penalty for Moira. Oliver asks Roy to help him find the Canary. 02x04 - Crucible Oliver discovers a man who goes by the name "The Mayor" is bringing illegal guns in to The Glades, so Oliver sponsors a "Cash for Guns" event to help clean up the city. Unfortunately, The Mayor crashes the event with his gang and seriously injures Sin. The Canary is furious when she learns her friend is in the hospital and sets out for revenge. Meanwhile, Felicity stuns Oliver with a bit of information about the Canary, Donner asks Laurel to dinner, and Diggle reconnects with an old friend. 02x05 - League of Assassins While Oliver tends to the Canary's wounds, he tries to get her to talk about where she came from but she refuses. However, after Oliver and the Canary are attacked at the Queen mansion by a trained killer from the League of Assassins, she confesses to how she's connected with the nefarious group. Meanwhile with Moira facing multiple counts of murder and conspiracy for her part in the destruction of The Glades, the Assistant District Attorney offers her a choice - plead guilty now and avoid the death penalty or take your chances in court. Thea begs her mother to fight for her life but Moira seems resolute about taking the offer. Meanwhile, Oliver is furious with Laurel for joining the prosecution's team on his mother's case. 02x06 - Keep Your Enemies Closer Amanda Waller sends A.R.G.U.S. agents to kidnap Diggle. Waller informs Diggle that Lyla has gone missing after following a lead on Deadshot in Moscow. When Diggle tells the team he's headed to Russia to rescue Lyla, Oliver and Felicity decide to join, but things get messy when Isabel shows up on the tarmac and insists on joining Oliver's "work trip." Meanwhile, Moira's lawyer, Jean, tells Thea that dating Roy, a known criminal, is hurting her mother's case. 02x07 - State Vs Queen Oliver is concerned when a mysterious illness sweeps the city, infecting hundreds of people, including Diggle. Oliver discovers Vertigo in Diggle's blood and realizes The Count has broken out of prison and is once again distributing his drug. Meanwhile, Moira goes on trial for her participation in the Undertaking. ADA Adam Donner collapses in court with Vertigo symptoms so Laurel must step in and try the case against Moira. Oliver is torn between standing by his family during the trial and catching The Count. However, things change when Felicity follows a lead and walks straight into a trap set by The Count. 02x08 - The Scientist A seemingly impossible robbery at Queen Consolidated's Applied Sciences Division brings Central City police scientist Barry Allen to town. Citing a similar case back home, Barry offers to help Oliver and team with the investigation. Oliver senses there is more to Barry than meets the eye, but he's distracted by the similarities between this current case and something that happened on the island. Meanwhile, Felicity takes a liking to Barry, which doesn't go unnoticed by Oliver. Sin asks Roy for help when a friend of hers goes missing. Roy is surprised when Thea not only encourages him to help, but joins the search. Unfortunately, Sin's friend is connected to Brother Blood, and their search ultimately gets one of them seriously injured. 02x09 - Three Ghosts 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 is killed. Roy is captured and tortured by Brother Blood. 02x10 - Blast Radius A bomber nicknamed Shrapnel has set his sites on Sebastian Blood, and Oliver dons his mask to protect his newfound ally. Meanwhile, Laurel investigates Sebastian's aunt who is locked up in a mental institution, and Thea learns about Roy's newfound superstrength. 02x11 - Blindspot Oliver is conflicted after Laurel reaches out to the Arrow asking him to investigate Sebastian Blood. Oliver is unsure whether to believe her accusations against the man he has publicly supported for mayor, but decides to trust Laurel. However, when the pair gets too close to the truth, Sebastian exposes Laurel's drug addiction and has her arrested. Meanwhile, Roy reveals his new super-strength to Sin who wants to test out his abilities. Unfortunately, Roy isn't able to contain his rage once unleashed and almost kills a man. Back on the island, Oliver is surprised when Sarah reveals a secret about Laurel. 02x12 - Tremors Arrow offers to train Roy so he can learn to control his newfound super-strength. However, Roy is a rebellious student and refuses to listen unless Arrow reveals his true identity, which Oliver refuses to do. Meanwhile, the Bronze Tiger escapes from prison and steals Malcolm's earthquake machine to sell to the highest bidder. Oliver, Diggle and Felicity attempt to stop the transfer, but Roy gets in the way, putting everyone in danger. Laurel is disbarred and spirals out of control. Moira is thrilled when Walter asks her to dinner, but his reason surprises her. Thea encourages her mother to ask Walter to reconcile. 02x13 - Heir to the Demon As Laurel continues to unravel, Oliver and Lance try to convince Sara to stay in Starling City and finally reunite with Laurel and Dinah. However, Sara's fellow League of Assassins member, Nyssa, comes to bring Sara back to the fold, but when Sara refuses, Nyssa kidnaps Dinah. Realizing she's putting her family in danger by staying in town, Sara considers re-joining the league. 02x14 - Time of Death A master hacker dubbed Clock King coordinates a series of raids on banks in Starling City, and his skills prove a match for Felicity. Meanwhile, Laurel's grudge with Sara continues and on the island, a pilot crashes his plane there and Sara tends to the dying man. 02x15 - The Promise In the present, Slade visits Oliver and makes his intentions clear. Five years earlier, Slade, Sara, and Oliver launch their assault on the Amazo, but things go wrong when Slade learns that Oliver was responsible for Shado's death. 02x16 - Suicide Squad Following Slade's return and his promise to make good on his threat to destroy Oliver's loved ones, Oliver focuses all his energy on preparing for battle with his former friend. Sarah tries to help but, fearing for her safety, Oliver pushes her away. Meanwhile, Diggle is recruited by Amanda Waller and A.R.G.U.S. to stop a warlord he knew from his time in Afghanistan. Always the solider, Diggle agrees to help. However, he's not prepared when Amanda introduces him to the rest of the team - Deadshot, Bronze Tiger, and Shrapnel, all criminals he and Arrow helped put away. Lyla defends the team and explains the world is a complicated place, but Diggle isn't sure he agrees. When the mission takes a dangerous turn, Diggle is forced to make a difficult decision. 02x17 - Birds of Prey Helena Bertinelli returns to Starling City to kill her father Frank, who has been captured by the police. Meanwhile, Assistant DA Donner offers Laurel her old job back if she will prosecute the case against Frank. And Oliver tells Roy that he will have to break up with Thea rather than risk hurting her during one of his fits of anger. 02x18 - Deathstroke Slade makes his move against Oliver and the repercussions are enormous. While Oliver scrambles to protect his family, a key player in his team starts to question Oliver's decisions. Meanwhile, Isabel makes her move to take Queen Consolidated away from Oliver. 02x19 - The Man Under the Hood When Oliver and his team destroy Slade's centrifuge, he attacks them as Deathstroke to get what he needs to find a replacement. Meanwhile, Laurel ponders what to do with Slade's information, and Oliver tries to convince Thea to help him protect their finances from Isabel. 02x20 - Seeing Red The Mirakuru sends Roy into an uncontrollable rage and he unleashes on the city. After Roy's deadly fight with a police officer, Oliver realizes the Mirakuru has taken over Roy completely and must figure out a way to stop him. Things get more complicated after Sara declares that Roy is too far gone and the only way to stop him is to kill him. Meanwhile, Thea believes she can break through to Roy so she goes on camera at Moira's campaign rally to lure him to Verdant. Her ploy works but after Roy attacks Thea, Team Arrow unleashes on him. 02x21 - City of Blood After Slade threatens to take everything Oliver loves away, Oliver decides the fastest way to stop further bloodshed is to surrender to his enemy. Knowing that surrender will surely lead to Oliver's death, Diggle and Felicity go to extreme measures to keep Oliver from confronting Slade. Meanwhile, Thea considers leaving town, and Laurel resumes her crusade against Sebastian Blood. Finally, Slade unleashes his assault on Starling City. 02x22 - Streets of Fire Laurel and the Arrow escape the tunnel and the vigilante sets out to get the Mirakuru cure and end the threat of Slade's super-soldiers. However, when Slade gets the cure first, the Arrow must negotiate with Sebastian Blood. Meanwhile, Laurel finds her sister and Amanda takes extreme measures to contain the super-soldiers. 02x23 - Unthinkable Slade moves forward with his plan to kill one more person in Oliver's life. While Oliver has fought all year to be more than the killer he once was, when Slade kidnaps someone close to Oliver's heart, Oliver is pushed to the edge and realizes sometimes it takes doing the unthinkable to stop the monster. Meanwhile, Diggle takes on Amanda Waller with a little help from some friends, and Thea turns to Roy in her time of need.