Quentin Lance's ongoing attempt to capture the vigilante is put to a halt when a recently released criminal kidnaps his daughter to get to Arrow. Meanwhile, John Diggle insists on spying on Moira Queen to learn her secrets.

The plan to kill Malcolm Merlyn goes into operation. Arrow kills one assassin who has just arrived in the city and retrieves his cellphone. It's up to Felicity to break into it and find out just who the target is. A birthday dinner for Tommy Merlyn is interrupted by his father who brings him a present. Tommy makes it clear that he is not welcome and does not want a relationship with him. Malcolm is to receive an award at a civic gala and after a heart to heart with Oliver, Tommy decides to attend. When Oliver learns that Malcolm is the target, he races to save Tommy. Once the attack begins, Malcolm and Tommy takes refuge in his office and Malcolm is about to reveal that he is the Dark Arrow but is seriously wounded before he can do so. Arrow arrives on the scene and to convince Tommy that he is there to help, reveals his identity.

Oliver awakens to find himself Malcolm Merlyn's prisoner. He manages to escape and away with help from Digg. Malcolm accelerates his timetable as a result. Felicity is questioned by Det. Lance about her hacking activities but is interrupted by Oliver who tells him about Malcolm's plan to destroy the Glades. Tommy confronts Oliver about Laurel but refuses to believe that his father is up to no good. Malcolm comes clean about his plans and Tommy realizes that his father is insane. Moira goes public with what she knows, urging the residents of the Glades to evacuate. Roy and Thea get caught up in the mayhem. While Oliver and Digg go after Malcolm, Felicity tries to neutralize the device via Lance. Malcolm has planned it all very well, however. In a flashback to his time on the island, Fyers attempts to bring down an airliner.

Diggle and Felicity return to the island to convince Oliver to return as the Arrow.

Now that Oliver no longer has the list to work from, he's not sure what's next. Roy continues doing his own vigilantism and has to be bailed out of jail by Thea. When he mentions to Oliver that someone is hijacking medical deliveries to the Glades Memorial hospital, the Arrow knows exactly what he wants to do. His visit to the hospital doesn't go well when local politician Sebastian Blood takes him to task for what his family has done. When he tries to stop a hijacking, Arrow comes up against China White and her new partner Bronze Tiger. Thea tells Roy she's not going to wait around until he gets killed. The flashback to the island shows the aftermath of Oliver's violent attack on the unknown visitor. Shado takes him in hand.

After taking a ride home from Slade, Thea becomes his prisoner. Can Oliver and his friends save her? Also, someone close to Oliver is working for Slade, since his return from the Island after Tommy's death.

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.

Lance continues his mission to take down the Arrow. When a meta-human named Jake Simmons, who kills people with blasts of energy and plasma, starts terrorizing Starling City, Oliver is forced to ask Ray for help.

Following the events of William's kidnapping, Darhk has become less powerful, but Carrie Cutter, a.k.a. Cupid, has emerged into Star City to cause chaos on the city and the Green Arrow.

After Laurel's death and the departures of both Diggle and Thea from Team Arrow, Oliver takes to the streets solo to protect Star City's citizens as the Green Arrow.

Three of Oliver's old foes break out of prison and form an alliance; Meanwhile, Lance is confronted about an old partnership.

When Vigilante attacks Oliver while he's acting as mayor, Diggle leads the team on a mission to stop Vigilante for good.

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

Oliver deals with the fallout of the explosion on the island.

William gets caught in the cross hairs as Oliver attempts to stop Cayden James with just the original Team Arrow.