With Oliver gone, Diggle, Arsenal, and Felicity have their hands full dealing with a new crime lord: Brick. Meanwhile, Ray prepares his battle armor, and in Tibet, a mysterious figure finds Oliver’s body.

Ra’s al Ghul sends Nyssa and her lieutenant to Starling City to inform Oliver that the League will kill 50 people a day until Sara’s murderer is turned over to them. With time running out, Oliver finally identifies the killer… and realizes that he can never turn them over for execution. Meanwhile, Ray shows Felicity his new project.

A crossover event that began on “The Flash” concludes with Oliver teaming with the Flash to stop a boomerang-wielding killer who plants five bombs in the city that are set to explode at the same time.

The Arrow is stalked by an ex-police officer who he rescued during the Mirakuru siege and has become dangerously obsessed with the hero. Meanwhile, Ray asks Felicity to accompany him to a business dinner, and Thea is forced to hire a new DJ for Verdant.

A killer is murdering his victims and attempting to frame Ted Grant. The Arrow finally comes to his aid after Laurel protests her trainer’s innocence. Meanwhile, Roy goes to Felicity for help determining if he killed someone under the influence of Mirakuru.

Felicity’s past as a crusading hacker is revealed when someone uses a super virus that she designed to bring Starling City to a standstill. Meanwhile, Oliver and Thea work on their new relationship, and Felicity’s mother pays a visit.

Nyssa believes that Malcolm killed Sara and goes after him to avenger her lover’s murder. Oliver discovers that he has no choice but to stop her, despite Laurel insisting that he avenger her sister’s death. Meanwhile, Thea returns to Starling City and settles in… until Nyssa discovers that she’s Malcolm’s daughter.

Oliver tries to track down Thea in Corto Maltese as Diggle searches for a missing field operative. Meanwhile, Felicity adapts to her new job.

A mysterious archer known as Komodo appears in town and begins skewering businessmen. Meanwhile, Oliver worries about Thea, which forces Roy to tell him the truth about why she left town; and Ray Palmer pursues Felicity. In a flashback, Oliver is assigned his first kill and the target is his best friend, Tommy.

With crime at an all time low, Oliver decides to take a break and asks Felicity on a date. However, they’re interrupted when a new drug dealer take the name of Count Vertigo and targets the Arrow for death. Meanwhile, Diggle becomes an expectant father and a scientist tries to acquire Queen Consolidated before Oliver can retake his family’s business.

As Oliver’s face off with Slade escalates, his resolve to the no-kill rule is tested. Especially as Slade targets the woman Oliver loves.

Oliver rallies his team as Slade’s soldiers attack the city. Felicity gets a call from S.T.A.R. Labs with game-changing news and Thea comes face-to-face with her father.

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.

The Mirakuru sends Roy into an uncontrollable rage and he unleashes on the city. Oliver realizes the Mirakuru has taken over Roy completely and must figure out a way to stop him.

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.

Sara and Roy become prisoners at the Slade and the only one who is able to save them is Oliver Queen.

The Huntress returns and takes hostages at the courthouse when her father is arrested. Laurel is among those taken, which prompts her sister, the Canary, to battle the Huntress in an epic confrontation. Meanwhile, Roy tries to keep Thea safe, but he doesn’t like the way he is forced to do it.

While Oliver deals with the pressure of Slade’s threats against Oliver and his loved ones, Amanda Waller with A.R.G.U.S. recruits Diggle for a black ops mission. Diggle is happy to learn that he’ll be working with his ex-wife Lyla… but not so thrilled that three convicts will be going on the mission with them.

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.

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.

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.

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.

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.

A bomber nicknamed Shrapnel has set his sights 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.

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.

When a superhumanly strong thief robs a Queen Consolidated warehouse, Central City police scientist Barry Allen comes to Starling City to investigate the case. However, despite his close working relationship with Felicity, Oliver suspects that there’s more to the young scientist than meets the eye. Meanwhile, Sin asks Roy to help investigate the disappearance of a friend. In the past, Oliver, Shado, and Sara try to get Slade to the submarine so they can use the serum to save his life.

The Count has a new scheme to turn Starling City’s residents into clients by addicting them to a new drug and then selling them Vertigo to cure it. among those stricken are Diggle and DA Donner, who collapses in the middle of presenting his case against Moira.

A.R.G.U.S. abducts Diggle and asks him to help recover Lyla from a Russian prison. Oliver and Felicity insist on going along to help and Isabel tags along. Meanwhile, Jean Loring advises Thea that her dating Roy is hurting Moira’s chance of getting an acquittal.

Oliver puts Sara Lance up at the manor and soon discovers that she doesn’t want to contact her family… both because she would put them in danger, and because she become a killer since the last time they saw her. Meanwhile, the League of Assassins send men to bring Sara back, alive or dead. And Oliver discovers that Laurel will be sitting second chair for his mother’s trial.

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.

When a dangerous criminal from Lance’s past escapes from prison, Felicity offers herself up as bait so Arrow, Diggle and Lance can capture him…but plans go awry.

Thieves hijack medical supplies sent to Glades Memorial. Oliver gets into a heated battle with China White and her new partner, the Bronze Tiger, over the supplies. Meanwhile, Laurel makes plans to catch the Arrow; and Thea give Roy an ultimatum.

Diggle and Felicity travel to the island of Lian Yu in search of Oliver, who left Starling City after the devastation of The Undertaking and his failure to avert it. Convinced to return home, Oliver finds that things are in much worse shape than he imagined – 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 Oliver’s mentors Slade, Shado and Oliver in a desperate situation.

Oliver and Diggle race to stop the Dark Archer from unleashing his vengeance on The Glades. However, they run into a roadblock after Detective Lance picks up Felicity for questioning. Tommy and Oliver’s already tumultuous relationship takes a turn for the worse after Oliver makes a confession about Laurel. After hearing of the danger in The Glades, Thea races to find Roy, inadvertently putting herself directly in the line of fire for Malcolm’s devious plan. On the island, Oliver, Slade and Shado are locked in a life-or-death struggle against Fyers as his missiles lock on a full Ferris Air jetliner.

With the Undertaking days away, Malcolm dons his black hood to conclude business with seismologist Dr. Brion Markov and his team. Oliver and Moira entertain a number of surprise – and mostly unwelcome – visitors. Hooded confrontations at home and the Meryln Global Group reveal dark secrets. Meanwhile, Roy and Thea are still looking out for a hero. Laurel makes a decision after Tommy’s revelation. In a flashback to the island, Oliver, Slade and Shado struggle to prevent Fyers from shooting a Ferris Air jet out of the sky. Paul Blackthorne and David Ramsey also star.

Finding it difficult to mend fences with Tommy and Diggle, Oliver instead focuses on crossing another name off the list. While digging through a crooked accountant’s laptop, Felicity discovers a transaction that could help Oliver find Walter. To reconfirm the lead, Oliver gambles that Felicity can be counted on in the field for the first time. In a flashback, Malcolm reveals to Robert Queen and Frank Chen painful details surrounding his wife’s murder, and how that shaped his plans for the Glades. Meanwhile, Tommy stuns Laurel with the truth.

Deadshot returns to Starling City after taking down a U.S. Ambassador and six others overseas. By keeping tabs on A.R.G.U.S.’s manhunt for the assassin, Oliver, Diggle, and Felicity learn that a sting operation is underway to capture Deadshot – alive. Diggle is determined to see his brother’s killer dead, with or without Ollie’s help. Meanwhile, Laurel takes drastic steps to protect a young witness, exacerbating friction between Tommy and Oliver. Later, Roy Harperunconventionally pursues all leads to find his new hero, but runs afoul of Detective Lance. Back on the island, Oliver recalls how Shado helped him incrementally gain confidence with a bow and hit the target for the first time.

When a young woman meets a violent death after partying at Verdant, Detective Lance and his new partner, Detective Hilton inform Oliver and Tommy that she was on the drug Vertigo. Oliver immediately pays a visit to the mental institution where The Count is locked up, but finds he is in no condition to deal drugs. However, when The Count escapes and Starling City is flooded with even more Vertigo-related violence, Oliver and Diggle make it their mission to track him down. After Detective Lance uncovers incriminating evidence against him, Tommy goes to great lengths to clear his name, and the fallout from his actions leads Tommy down a new, unexpected path. In a flashback to the island, Oliver recalls the lessons he learned from Slade and Shado.

An angry resident of The Glades who calls himself “The Savior” embarks on a kidnapping and killing spree to punish those he believes have wronged the residents of his neighborhood. To make things worse, he broadcasts these murders online and claims he was inspired by Arrow’s vigilantism. Oliver is horrified by this statement and vows to stop “The Savior,” but his manhunt in intensified after Thea comes to him in tears and tells him Roy has been kidnapped. Laurel is surprised when her father starts to believe her mother’s claim that Sara is still alive. Meanwhile, Malcom tells Moira to find the person responsible for his attempted murder.