Nu hvor Arrow har fået styr på kriminaliteten i Starling City, forsøger han at leve et roligt og normalt liv. Men den plan går hurtigt i vasken, da en 'ny' Count Vertigo' begynder at sælge stoffer i byen.

Oliver og holdet leder efter Saras morder og sporene peger på Komodo, en mand som målrettet eliminerer sine ofre, én efter én.

Oliver tager til Corto Maltese for at hente Thea hjem, mens Lyla beder Diggle om at finde en savnet fra A. R. G. U. S. .

Nyssa er overbevist om, at Malcolm er Saras morder, men Oliver deler ikke hendes tro.

Felicitys mor, Donna, ankommer til tarling City samtidig med en terrorgruppe der kalder sig selv 'Brother Eye'.

A killer is murdering his victims and attempting to frame Ted Grant. The Arrow finally comes to his aid after Laurel protests her trainer's innocence. Meanwhile, Roy goes to Felicity for help determining if he killed someone under the influence of Mirakuru.

The Arrow is stalked by an ex-police officer who he rescued during the Mirakuru siege and has become dangerously obsessed with the hero. Meanwhile, Ray asks Felicity to accompany him to a business dinner, and Thea is forced to hire a new DJ for Verdant.

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.

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.

With Oliver gone, Diggle, Arsenal, and Felicity have their hands full dealing with a new crime lord: Brick. Meanwhile, Ray prepares his battle armor, and in Tibet, a mysterious figure finds Oliver's body.

Brick takes three city aldermen hostage and demands that Mayor Castle turn the Glades over to him in return for their safe return. Meanwhile, Felicity turns to Ray for help when she needs a helicopter, and Laurel realizes that she may be in over her head with her new crime fighting carer.

Brick and his men take over the Glades, and the police are helpless to stop them. With Oliver nowhere to be found, the team seems helpless. Meanwhile, Oliver tries to convince Tatsu to return with him to Starling City, and Malcolm's past before his training at Nanda Parbat is seen.

Malcolm puts Oliver and Thea in a dangerous situation that lands them on Lian Yu with Oliver's former enemy Deathstroke. In a flashback, Oliver and Maseo return to Starling City to retrieve the Omega bio weapon.

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.

After hearing Ra's al Ghul's offer, Oliver returns to Starling City and contemplates whether he should accept it or not. Meanwhile, Quentin turns against the Arrow, and a new villain--Murmur--comes to the city to get revenge.

While the Arrow tries to track down the imposter killing criminals, Amanda calls Lyla in for a Suicide Squad mission and Diggle insists on accompanying his new wife. However, the Squad soon discovers that their rescue mission isn't what they expected. Meanwhile, Ray learns that Oliver is the Arrow and sets out to bring him in for his crimes.

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.

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 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 sets out to transform Oliver into his perfect heir. Meanwhile, Nyssa and Laurel draw closer, but their mentor/student relationship is threatened when Ra's sends men to bring his errant daughter back to Nanda Parbat..

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.

With time running out for Starling City, Oliver tries to stop Ra's from unleashing the bioweapon and killing millions.