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.

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.

After eight seasons, and the launch of countless superheroes, the series wraps up the story of the Green Arrow.

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.

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.

After Roy confesses that he's the Arrow, Oliver is forced to lie low as Quentin continues his quest to prove that Oliver is the real Arrow. Meanwhile, a metahuman kills two bank guards and Oliver is forced to turn to Ray--as the Atom--for help.

Oliver returns to Starling City on Earth-2, where he encounters familiar faces while trying to decipher the Monitor's mission. Meanwhile, Mia and William's team clash with a new foe.

After being double-crossed by Lyla, Oliver finds himself facing a life or death situation that seems very familiar. Laurel has the opportunity to make amends with the past.

After Oliver is shot, he turns to a surprising person for help - Felicity. Diggle is stunned when he sees Felicity walk through the front door of the lair dragging a dying Oliver behind her, and the two team up to save Oliver's life. As Oliver hovers between life and death, he flashes back to a seminal event on the island - a daring escape attempt with his new friend Slade Wilson.

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.

Thea betrays Malcolm to the League, but Oliver sets out to rescue his lover's killer so that Thea won't suffer the guilt of arranging for a parent's death. In the past, Oliver and the Yamashiros are released from custody, but Amanda Waller has other plans.

Ra's makes his next move against Oliver by reveling the Arrow's secret identity to Quentin. Left without alternatives, Oliver has no choice but to surrender. Meanwhile, Ray is injured in an attack and Felicity must take a risk to save his life.

Oliver assembles a group of unlikely allies - Slade, Nyssa, Merlyn and Digger Harkness - to engage in an epic battle against Chase and his army.

The pressure mounts for Oliver who begins to wonder if he will lose everything in his battle to save Star City. A familiar face returns.

Oliver and Diggle learn that Deadshot is still alive and his next target is Malcom. Malcom invites Tommy to attend a benefit honoring Malcom for his work with Starling City but Tommy refuses to attend. Oliver encourages his friend to mend his relationship with his father while he can. Meanwhile, Oliver struggles to balance his new relationship with McKenna and his duties as Arrow.

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.

Oliver has no choice but to accept Ra's's offer to resurrect Thea. In return, Oliver must become the Heir to the Demon.

Ra's tells Nyssa that she must marry Oliver or face death. Meanwhile, an unexpected ally travels to Starling City to ask Diggle, Felicity, and Laurel to help infiltrate Nanda Parbat. In the past, Maseo and Oliver try to find the cure for Akio before it's too late.

Barry and Iris’s wedding brings the gang together, but things go awry when villains from Earth-X attack the ceremony. All of the superheroes band together with help from their super friends like Citizen Cold, The Ray, Felicity Smoak, Iris West and Alex Danvers to take on their most formidable villains yet. Earth’s mightiest heroes – Green Arrow, Supergirl, The Flash and White Canary – lead their teams into battle to save the world. The crossover starts on Supergirl S03E08 Crisis on Earth X (I). It continues on The Flash S04E08 Crisis on Earth-X (III) and DC's Legends of Tomorrow S03E08 Crisis on Earth X (IV).

With a new ally on his team, Oliver engages Diaz in an epic final battle.

When a mysterious new Deathstroke appears in Star City, Oliver and Team Arrow insist on taking down this villain themselves. Meanwhile reeling from the loss of one of their own, the future Team Arrow figures out a new way to try and stop JJ.

Oliver's mission takes him to Lian Yu where he tries to ignore the repercussions of the looming Crisis until he receives help from an old friend. Meanwhile, a united Team Arrow faces a recognisable villain.

Slade returns and asks Oliver for help in tracking down his son. When they learn Joe has been taken hostage by mercenaries, their mission to save him gets complicated by a terrible revelation that could shatter Slade's hopes of reunion forever. Meanwhile, Vigilante reappears in Star City.

In his darkest place yet, Oliver wonders if he has failed at everything – being a father, a mayor and a hero. His frustration rising, Oliver lashes out at Felicity and William. A surprising visit from an old friend has Oliver questioning his next move.

Reunited with his sister, Oliver and Thea find themselves searching through a familiar maze of catacombs. Meanwhile, John and Lyla partner on a special ops mission.