Episode 2x01: City Of Heroes (Oct/09/2013)
Diggle and Felicity convince Oliver to return to Starling City despite the fact he blames himself for Tommy's death. He only returns to save Queen Consolidated, but soon becomes embroiled in a crisis when several men using the name of The Hood start killing the rich to get revenge for the Undertaking... and Thea Queen is their next target. Meanwhile, in the past on the island, Oliver, Slade, and Shado kill Fyers and his men, but soon receive a visit from someone new.
Episode 2x02: Identity (Oct/16/2013)
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.
Episode 2x03: Broken Dolls (Oct/23/2013)
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.
Episode 2x04: Crucible (Oct/30/2013)
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.
Episode 2x05: League of Assassins (Nov/06/2013)
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.
Episode 2x06: Keep Your Enemies Closer (Nov/13/2013)
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.
Episode 2x07: State v. Queen (Nov/20/2013)
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.
Episode 2x08: The Scientist (Dec/04/2013)
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.
Episode 2x09: Three Ghosts (Dec/11/2013)
After covering from a near-fatal drug overdose, Oliver begins hallucinating people from his past. Believing he's a liability, Oliver gives the information he has on Cyrus Gold to Quentin... which results in the deaths of several police officers. Meanwhile, Brother Blood captures Roy and uses him as a test subject for his new serum. In the past on the island, Ivo gives Oliver an impossible choice to make.
Episode 2x10: Blast Radius (Jan/15/2014)
Oliver must tackle a new threat to the city when bombs start to go off in Starling City. Felicity discovers the person setting them off is Mark Sheffner, a man who goes by the nickname Shrapnel. Arrow discovers Shrapnel's next target is Sebastian Blood's "Unity Rally" and tries to talk the alderman out of hosting it, but he refuses. Arrow sets off to stop the bombing, but Shrapnel tricks him and traps him in a bomb-laced antique store where he is unable to move without setting off the device. While Felicity helps Oliver, Diggle races to the plaza to find the bomb before it goes off. Meanwhile, Roy continues to hide his new strength from Thea, but, after she witnesses his super strength in action at the rally, she demands answers. Laurel's suspicions about Sebastian grow stronger once she learns that he grew up with Cyrus Gold, the man who killed Lance's partner. After Donner refuses to help her investigate, she turns to Arrow for help.
Episode 2x11: Blind Spot (Jan/22/2014)
When her father won't believe her accusations against Sebastian, Laurel turns to the Arrow for help. Oliver has his own doubts about Laurel, particularly when she is arrested on a charge of drug possession. Meanwhile, Roy sets out to test his new abilities but goes berserk, putting a man in the hospital.
Episode 2x12: Tremors (Jan/29/2014)
While the Arrow trains Roy how to control his anger--and his super-strength--Bronze Tiger steals a prototype of Malcolm's earthquake machine to sell to an arms dealer. Meanwhile, Laurel discovers that she's being disbarred and goes out of control, and Walter has an offer for Moira. On the island, Oliver wonders whether to tell Slade the truth about how Shado died.
Episode 2x13: Heir To The Demon (Feb/05/2014)
Sara returns to Starling City at Oliver's request to check on Laurel, and both he and Quentin would like her to stay. her situation becomes precarious when a member of the League of Assassins arrives in town and sets out to persuade Sara to fulfill her vow and return to the organization... no matter what it takes. Meanwhile, Felicity discovers Moira's secret and must choose whether to tell Oliver or not.
Episode 2x14: Time Of Death (Feb/26/2014)
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.
Episode 2x15: The Promise (Mar/05/2014)
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.
Episode 2x16: Suicide Squad (Mar/19/2014)
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.
Episode 2x17: Birds of Prey (Mar/26/2014)
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.
Episode 2x18: Deathstroke (Apr/02/2014)
Isabel reveals her true allegiance as Slade makes his move on Oliver, abducting Thea and putting Oliver's secrets at risk. Meanwhile, Roy grows increasingly impatient with Oliver, who he believes put Thea in danger by forcing Roy to break up with her.
Episode 2x19: The Man Under The Hood (Apr/16/2014)
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.
Episode 2x20: Seeing Red (Apr/23/2014)
Roy goes on a rampage under the influence of Mirakuru and ends up killing a policeman. While Sara and Oliver argue about how to deal with their friend, Moira considers whether to drop out of the mayoral race to repair her relationship with Thea.
Episode 2x21: City Of Blood (Apr/30/2014)
After the death of someone close to him, Oliver decides to give himself up to Slade rather than risk further bloodshed on his friends and family. Meanwhile, Laurel renews her investigation into Sebastian Blood, and Slade makes his final plans to unleash his Mirakuru-enhanced army on Starling City.
Episode 2x22: Streets Of Fire (May/07/2014)
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.
Episode 2x23: Unthinkable (May14/2014)
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.
Source: TVRage