Oliver and Barry Allen take Kendra Saunders and Carter Hall to a remote location to keep them hidden from Vandal Savage while they figure out how to defeat him. Malcolm arranges a meeting between Vandal, Green Arrow and The Flash that doesn’t go as planned. Meanwhile, Felicity, Thea, Diggle and Laurel work with Team Flash to come up with a weapon powerful enough to destroy Vandal Savage.

The crossover starts on The Flash S02E08 Legends of Today (I).

Oliver and team uncover HIVE’s plan to take out Team Arrow once and for all. With HIVE’s next attack imminent, Lance wonders if Donna is safer without him in her life. Meanwhile, with the wedding fast approaching, Oliver begins to feel guilty that he hasn’t told Felicity about his son.

Oliver realizes he needs help battling Darhk so he calls in an old friend – Vixen. Using her magical ability to summon animal powers, Vixen gets a lock on Darhk's location and the team goes to war. Meanwhile, Thea has a heart-to-heart talk with Malcolm.

Oliver and Felicity get trapped in the bunker together, while Diggle and Lyla deal with marital issues.

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.

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 deals with the fallout of the explosion on the island.

Oliver tries to balance being the mayor, Green Arrow and a father to William. Anatoly returns to Star City with a deadly agenda.

A rogue black ops team led by Onyx breaks into Kord Industries and steals something lethal. Oliver struggles to connect with William so he reaches out to a surprising source for help.

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.

As Slade continues to uncover clues about his son’s last few years, Oliver makes a big decision. Meanwhile, the Green Arrow leads the team into battle against “The Dragon,” a villain who is stealing valuable tech in Star City.

Oliver celebrates Thanksgiving with his family but the happy moment is interrupted. Meanwhile, Black Siren returns to wreak havoc on the holiday.

Quentin Lance is kidnapped by Black Siren and Cayden James, who are looking to trade Lance’s life for a weapon of mass destruction. Oliver and Team Green Arrow must figure out a way to save Lance while still keeping the city safe.

Cayden James ups the ante by launching his plan to take control of every aspect of the city. Despite the scope of Cayden’s plan, Oliver is determined to foil it with just the Original Team Arrow – and without the aid of Rene, Dinah, or Curtis. But things get complicated when William is endangered as a result of Cayden’s handiwork.

Cayden James discovers a secret about the Green Arrow that pushes him over the edge. Knowing everyone and everything he loves is in danger, Oliver must decide if he can do this alone or if he needs to turn to his old teammates for help. William starts to demand more of Oliver’s time.

Oliver, Diggle and Felicity disagree with Dinah, Curtis and Rene on how to handle Black Siren. The two teams face off and a fight ensues.

Nyssa Al Ghul returns to Star City to warn Thea that a group of renegade League of Assassins members are planning to attack her. This group, led by Athena, is intent on finding a mysterious box that Malcolm left behind and will stop at nothing to get it. Nyssa helps Oliver come to a life-changing realization.

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.

Oliver turns to an old friend to help battle Diaz; Rene is out of the hospital but has a hard time readjusting to life as Wild Dog; Lance discovers something shocking about Black Siren.

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.

Diaz targets Team Arrow and their loved ones. Oliver struggles with Felicity putting herself in danger when she gets the chance to stop Diaz for good.

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

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 makes a drastic move in his quest to find Diaz. Like her husband, Felicity pulls out all the stops to get to Diaz. Meanwhile, when arsonists target Rene’s community center, injuring Zoe in the process, the mysterious new Green Arrow swoops in to help save the day. Faced with pressure from the mayor to capture the vigilante, Dinah must decide if following the rules at all costs is the best plan to keep the city safe.

A documentary entitled “The Hood and the rise of vigilantism” starring Oliver Queen, Felicity Smoak, and the rest of Team Arrow. As a camera crew follows Oliver and team around to talk about their past as vigilantes and what the Green Arrow means to Star City, Oliver must also deal with William’s return from boarding school as well as a new threat to the city. The episode will feature “documentary footage” captured by the BTS crew and interviews from those who have worked alongside the Green Arrow.

Oliver and Felicity are disappointed after they learn that William is hiding something from them. Wanting to focus on his family, Oliver steps back from his Green Arrow duties and let’s the team take over tracking down a serial killer. However, when the team becomes targets for the killer, things take a bloody turn.

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