With the city in a relative peace Oliver considers the possibility of a relationship with Felicity -- unaware that a new crime lord is targeting him with a terrible new form of Vertigo. A charismatic young executive makes a play for Queen Consolidated, and in the past Oliver finds himself in Hong Kong under the thumb of Amanda Waller.
Reeling from the murder of one of their own, the team tracks an archer assassin across the city. Meanwhile Laurel decides to take matters into her own hands, and Felicity receives a new job offer. Five years ago in Hong Kong, Oliver is in a bind when Amanda Waller orders him to kill his best friend.
Oliver tracks Thea to the island of Corto Maltese, where he hopes to convince her to home home -- even if he has to reveal his secrets. Meanwhile Lyla asks Diggle to go along in search of one of her field operatives, who has gone dark.
Nyssa arrives in Starling City and is stunned to learn of Sara's fate, joining Oliver and the team in tracking down a man believed to be dead: Malcolm Merlyn. Meanwhile Thea returns to town, and Oliver and Laurel have a dispute over how to take revenge.
When a hacker brings the city to its knees with a series of cyber attacks, Felicity suspects that someone from her past may be involved. Meanwhile her mother pays Felicity a surprise visit.
A series of gang-related murders points Oliver to a serial killer with a personal grudge, and Laurel's friend Ted Grant becomes his lead suspect. Meanwhile Roy confides in Felicity about his dreams, and in the past Oliver is tasked with finding information being sent through Hong Kong by China White.
Oliver faces a female archer who is obsessed with the Arrow, and has taken up serial killing to get his attention. Meanwhile, Ray asks Felicity to be his date for a work dinner with important clients. In the past, Oliver and Tatsu go in search of her missing husband.
The hunt for a boomerang-wielding assassin leads Arrow's team to A.R.G.U.S., and the Flash and his team show up in Starling to offer their help. Oliver and Barry clash over their methods, and in the past Waller orders Oliver to extract information from a prisoner.
Impatient with Oliver's failure to find Sara's killer, the League of Assassins gives the Arrow 48 hours until they start killing Starling's citizens. Laurel is surprised when her mother Dinah comes to visit.
Felicity, Diggle, and Roy try to continue their work in Oliver's absence, not knowing if their friend is alive or dead. Merlyn pays the team a surprise visit, and in the past Oliver and Maseo lead an op to recover something taken by China White.
Laurel attempts to take her sister's place defending the city as the Canary, but Roy and Diggle worry that her inexperience will get her killed when Brick kidnaps the city's Aldermen. In the past, Oliver and Maseo enter China White's den to try and save Maseo's wife.
When the police meet a criminal overlord's demand to withdraw from the Glades, Team Arrow is forced to accept help from Malcolm Merlyn to protect the district's desperate citizens. Malcolm recalls his path to the League of Assassins following the murder of his wife.
After the new Count Vertigo escapes from federal custody Laurel is dosed with his hallucinogenic drug, putting her face-to-face in a fight with her sister -- and herself. Oliver is convinced to reveal his secret to someone close to him, and in the past Amanda Waller catches up with Oliver.
Oliver and Thea begin training on the island of Lian Yu, only to discover that Slade Wilson is now free of his prison. In the past, Oliver and Maseo arrive in Starling City on a covert mission that takes them into the heart of Queen Consolidated.
Malcolm is captured by Ra's al Ghul and taken to Nanda Parbat. Because of his love for Thea, Oliver considers saving Merlyn. Ray is obsessed with finishing his Atom suit so he can save the city but Felicity fears he is heading down the same path as Oliver and tries to pull him out of the lab. (The CW)
Following an encounter with Ra's al Ghul Oliver returns home to weigh a decision that could change the course of his life. A man with his lips sewn shut leads a new criminal crew in Starling, and in the past Oliver must protect young Akio.
When the League of Assassins frames the Arrow for a killing spree, Ray Palmer attempts to discover the vigilante's true identity. Lyla and Diggle's honeymoon is interrupted when Deadshot recruits them for a mission to rescue a U.S. Senator from a hostage situation on foreign soil.
Detective Lance is on the warpath after the League of Assassins frames the Arrow for murder, putting Oliver and his friends in his crosshairs. Ray's life hangs in the balance after he is shot, and in the past Oliver encounters Shado's twin sister.
With Roy in prison and the Arrow sidelined by Detective Lance's relentless pursuit, the Atom must go toe-to-toe with a meta-human who has arrived in Starling City. In the past, Oliver discovers that Argus's Hong Kong have been overrun.
Ra's al Ghul's attack on someone close to Oliver's heart forces him to return to Nanda Parbat and take desperate measures. In the past Oliver, Maseo, and Tatsu try to stop the deployment of a deadly bioweapon.
Team Arrow is convinced that Oliver has been brainwashed by the League of Assassins when he returns to Starling City to kill Nyssa, who has been bonding with Laurel since becoming a League outcast.
On the eve of Oliver's wedding to Nyssa, Malcolm leads his friends on a mission to stop Ra's genocidal attack on Starling City. Thea pays Roy a visit, and in the past Oliver and Maseo make a desperate attempt to save Akio's life.
Oliver heads toward a final confrontation with Ra's al Ghul as the League of Assassins implements his final plan. As his team joins together to save Starling City, Oliver makes a deal with the devil.
