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

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.

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.

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.

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.

Oliver makes a choice that will affect his entire life, as well as the lives of everyone he cares about.

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

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

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 Prometheus attacks Curtis, Oliver realizes Prometheus knows all of Team Arrow’s secret identities and is planning to come for them one by one. Felicity and Detective Malone discover a clue that links Prometheus to Oliver’s past.

Prometheus goes to extreme lengths to destroy Oliver. In flashbacks, Oliver's violent tendencies come to a head in a confrontation with Anatoly.

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.

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.

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.

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.

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.

Oliver wakes up to a life where he never got on The Queen’s Gambit. Robert and Moira Queen are alive and well. Laurel is his loving fiancée and their wedding is imminent. Everything seems perfect, but Oliver starts to notice small imperfections that make him question this new reality. Meanwhile, Felicity and the recruits take on a new threat with help from The Flash and Supergirl. The crossover starts on Supergirl S02E08 Medusa (I) and The Flash S03E08 Invasion! (II). It continues on DC's Legends of Tomorrow S02E07 Invasion! (IV).

Black Siren returns to give Chase help; Felicity plans a birthday party for Oliver; Lance is angry with Rene for missing the custody hearing about his daughter.

Following Oliver’s shocking decision to turn himself over to the FBI and reveal his identity as the Green Arrow to the public, Oliver has spent the past five months in Slabside Maximum Security Prison. Determined to keep a low profile to shorten his sentence for the sake of his family, Oliver is tested when he runs into old foes. Meanwhile, Diggle and Dinah have taken on new jobs and left their costumes behind but not everyone is following suit. With her focus on William, Felicity tries to start over but when someone from her past resurfaces, things become complicated.

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.

Oliver gets closer to the truth about Prometheus. Meanwhile, Helix refuses to continue helping Felicity until she does a favor for them.

With Oliver and Barry still stuck in the other’s bodies, the two get a lead on John Deegan and head to Gotham City with Supergirl to figure out why their reality has changed. While there, they meet the mysterious Kate Kane who provides them with information that leads the group to Arkham Asylum. The crossover starts on The Flash S05E09 Elseworlds (I) and concludes on Supergirl S04E09 Elseworlds (III).

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.

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.