Billionaire playboy, Oliver Queen, has been considered dead for five years. Now, he has returned. But something, during those five years, has changed him into a mysterious green hooded archer.

Arrow moves further along his father's list while battling family issues with his mother, Moira, and especially with his sister. He also makes amends for past difficulties with Laurel.

A mysterious sniper called Deadshot is taking out bidders at an auction for an industry company. The bidders include Oliver's stepfather, Walter Steele.

Peter Declan has been charged with murdering his wife, and only Oliver believes he's innocent. Arrow asks Laurel to look into Declan's case. Meanwhile, Walter investigates a warehouse that Moira mysteriously bought with the company's money.

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's next target is Scott Morgan, a power executive who jacks up prices for electricity when people most need it. John Diggle suggests they go after the gang of bank robbers that recently wounded a police officer during a daytime heist. Oliver is not so keen but John isn't the kind of guy who gives up very easily. Oliver quickly identifies one of them as a high school acquaintance, Derek Reston - and learns that Reston may have turned to crime because of something Oliver's father did. Tommy meanwhile isn't having much luck with his hoped for romance with Laurel. He seeks Thea's advice. Flashbacks show Oliver's doubts about his survival on the island.

A new vigilante is killing off the people that work for mob boss Frank Bertinelli.

Oliver Queen attempts to train Helena Bertinelli in the hopes that she will join him in his fight for justice. Meanwhile, Walter Steele delves deeper into his wife's secrets.

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.

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.

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.

A jewel thief named Dodger strikes Starling City, a purse snatcher targets Thea and dating anxiety hits Oliver and Diggle. Each perilous situation leads to hard choices.

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.

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.

Vertigo is again appearing on the market even though The Count, who created the drug, is still in a psychiatric hospital. Soon after Oliver confirms that he's still there, he somehow manages to escape. The Count's psychiatrist says his patient overpowered him and has concluded that his insanity was just a ruse. The police suspect Tommy may be dealing drugs from the club and Det. Lance gets a search warrant. Oliver is not sure what to believe and Tommy, feeling his onetime friend has no respect for him, quits. He turns to his father for a job. Digg gives information about Deadshot to a former intelligence colleague. On the island meanwhile, Oliver begins to learn how to use a bow.

Oliver decides that his next target is going to be someone on Digg's list: Deadshot. They set a trap for him and Digg's spy friends get involved as well. Meanwhile, Laurel's latest clients are Eric and Nancy Moore who have agreed to testify against Edward Rasmus, a financial advisor who swindled them. The night before their deposition however, they are assassinated. Laurel takes charge of their now orphaned son, Taylor, but he saw his parents killed and is now the assassins next target. Oliver steps in to stop him but in doing so fails to back up Digg and Deadshot escapes. It creates a rift and Diggs walks out. A flashback to the island show Oliver, Wilson and Shado are preparing to free Yao Fei.

After taking a mob accountant's laptop, Oliver plans to return the money to its rightful owners. Felicity however finds that Dominic Alonzo - the operator of an illegal casino and the head of a gang known for kidnapping - was paid $2 million to kidnap Walter. Arrow pays him a visit and is told that Walter is dead. He tells his mother and Thea but Moira rushes to Malcolm Merlyn demanding to know why he broke their agreement. He assures her that Walter is alive and will be released as long as she continues to cooperate. Oliver is listening to the entire conversation and now knows that his mother is involved, just as Digg had warned him. Flashbacks reveal Malcolm's plan and also the the sinking of Robert Queen's luxury yacht was no accident. Laurel meanwhile tries to make up with Tommy and finally learns the real reason he broke up with her.

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.