Oliver is accused of being the hooded archer and is put under house arrest. Also, he thinks back to his time on the island, where he first met Edward Fyers and Deathstroke.

Oliver Queen attempts to track down a mysterious copycat vigilante who is killing people on the list.

Oliver's confidence is shaken after being beaten by the Dark Archer and he takes a break from being Arrow. However, when Laurel calls Arrow for help investigating a firefighter's suspicious death, he reluctantly agrees but his hesitance while fighting almost costs him his life. Meanwhile, Tommy throws a benefit for the firefighters and Thea tries to lift Moira out of her depressive state.

After a string of violent armored car robberies, Oliver suspects that Ted Gaynor of Black Hawk Security is the mastermind. His name is also on the list. It leads to a major disagreement with Digg as Gaynor was his training officer on his first tour of duty in Afghanistan. Digg learns that people change. Meanwhile, Tommy is hesitant at his father's attempt at reconciliation - and with good reason. Thea celebrates a birthday but has trouble with the police when she's arrested after a car accident for driving under the influence of a narcotic.

After Thea gets in trouble with the police, Oliver turns to an old flame - now a vice cop - to help track down the creator of a new designer drug with lethal after-effects.

Oliver's heavy-handed approach to getting information from his mother backfires and she manages to shoot him in the shoulder. He turns to Felicity Smoak for help getting back to his hideaway. She and Digg do their best to nurse him back to health. Flashbacks to Oliver's time on the island reveals an early attempt to escape. Oliver's loyalties however prevent him from taking advantage of the situation. The reason for Yao Fei's betrayal is revealed.

Helena is back to seek vengeance, but Oliver still has feeling toward her. The Arrow must stop and kill her, but at what costs? Now that several of his closest friends know about his true identity, no one is safe.

After a major fire, Oliver decides it's time to eliminate real estate developer and slumlord John Nicol, another person on his father's list. He's beaten to the punch when another vigilante, The Savior, who kidnaps Nicol and ultimately executes him - broadcasting the whole thing over the Internet. The new vigilante is identified as a man whose wife was killed in a bodega robbery in the Glades district. When he kidnaps Thea's new boyfriend, Roy Harper, Oliver decides to stop him. Meanwhile, Laurel is upset to find that her father has come around to her mother's belief that her sister may still be alive. In a flashback to his days on the island, Oliver learns why Yao Fei refused to leave.

The time is fast approaching for the Undertaking to occur and Malcolm Merlyn begins to tidy up the loose ends, beginning with the scientists at UNIDAC. Oliver and Digg trick Moira into telling just what the Undertaking is about. Oliver realizes that even if he manages to eliminate everyone on his father's list he has only, in his own words, eliminated the symptoms and not the disease. Felicity locates the UNIDAC device - sort of. Thea and Roy's relationship comes to head when they are unable to locate the vigilante. Walter files for divorce. Laurel and Oliver begin a new relationship. In a flashback to his time on the island, Oliver learns just what Edward Fyers' plan is.

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.

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 recognizable villain.