1. City of Heroes

UK airdate: 21 October 2013

Diggle (David Ramsey) and Felicity (Emily Bett Rickards) travel to Lian Yu in search of Oliver (Stephen Amell) who left Starling City after The Undertaking. Convinced to return home, Oliver finds that things are in worse shape than he thought – Isabel Rochev (guest star Summer Glau) is preparing a hostile takeover of Queen Consolidated, Thea (Willa Holland) refuses to visit Moira (Susanna Thompson) in jail, Roy (Colton Haynes) is trying to fill the void left by the Arrow’s absence, and Laurel (Katie Cassidy) is working with the District Attorney’s office to take down the vigilante. Meanwhile, flashbacks to the island show Slade (Manu Bennett), Shado (guest star Celina Jade) and Oliver in a desperate situation.

2. Identity

UK airdate: 21 October 2013

Oliver finds out the medicine that is being sent to Glades Memorial is being hijacked by thieves. Without an influx of supplies, the hospital will close. Roy attempts to stop the thieves, but he fails and is arrested by Officer Lance. Oliver gets into a heated battle with China White (guest star Kelly Hu) and her new partner, Ben Turner, AKA the Bronze Tiger (guest star Michael Jai White), over the supplies. Meanwhile, Laurel (Katie Cassidy) makes plans to catch the Arrow, and Thea (Willa Holland) gives Roy an ultimatum.

3. Broken Dolls

UK airdate: 28 October 2013

Lance (Paul Blackthorne) learns a criminal named Barton Mathis (guest star Michael Eklund), whom he put away years ago, broke out of prison during the quake and is back to torturing and murdering women. Felicity (Emily Bett Rickards) offers herself as bait so Arrow (Stephen Amell), Diggle (David Ramsey) and Lance can catch this villain, but the plan goes awry. Furious, Mathis kidnaps Laurel (Katie Cassidy) in retaliation and plans to murder her while Lance watches. Meanwhile, Thea (Willa Holland) and Oliver are stunned when District Attorney Adam Donner (guest star Dylan Bruce) seeks the death penalty for Moira (Susanna Thompson). Oliver asks Roy (Colton Haynes) to help him find the Canary (Caity Lotz).

4. Crucible

UK airdate: 4 November 2013

Oliver (Stephen Amell) discovers a man who goes by the name “The Mayor” (guest star Cle Bennett) is bringing illegal guns in to The Glades, so Oliver sponsors a “Cash for Guns” event to help clean up the city. Unfortunately, The Mayor crashes the event with his gang and seriously injures Sin (guest star Bex Taylor-Klaus). The Canary (Caity Lotz) is furious when she learns her friend is in the hospital and sets out for revenge. Meanwhile, Felicity (Emily Bett Rickards) stuns Oliver with a bit of information about the Canary, Donner (guest star Dylan Bruce) asks Laurel (Katie Cassidy) to dinner, and Diggle (David Ramsey) reconnects with an old friend.

5. League of Assassins

UK airdate: 11 November 2013

While Oliver (Stephen Amell) tends to the Canary’s (Caity Lotz) wounds, he tries to get her to talk about where she came from but she refuses.  However, after Oliver and the Canary are attacked at the Queen mansion by a trained killer from the League of Assassins, she confesses to how she’s connected with the nefarious group.  Meanwhile with Moira (Susanna Thompson) facing multiple counts of murder and conspiracy for her part in the destruction of The Glades, the Assistant District Attorney (guest star Dylan Bruce) offers her a choice – plead guilty now and avoid the death penalty or take your chances in court.  Thea (Willa Holland) begs her mother to fight for her life but Moira seems resolute about taking the offer.  Meanwhile, Oliver is furious with Laurel (Katie Cassidy) for joining the prosecution’s team on his mother’s case.

6. Keep Your Enemies Closer

UK airdate: 18 November 2013

Amanda Waller (guest star Cynthia Addai-Robinson) sends A.R.G.U.S. agents to kidnap Diggle. Waller informs Diggle that Lyla (guest star Audrey Marie Anderson) has gone missing after following a lead on Deadshot (guest star Michael Rowe) in Moscow. When Diggle tells the team he’s headed to Russia to rescue Lyla, Oliver and Felicity decide to join, but things get messy when Isabel (guest star Summer Glau) shows up on the tarmac and insists on joining Oliver’s “work trip.” Meanwhile, Moira’s (Susanna Thompson) lawyer, Jean (guest star Teryl Rothery), tells Thea that dating Roy, a known criminal, is hurting her mother’s case.

7. State V. Queen

UK airdate: 25 November 2013

Oliver is concerned when a mysterious illness sweeps the city, infecting hundreds of people, including Diggle. Oliver discovers Vertigo in Diggle’s blood and realizes The Count (guest star Seth Gabel) has broken out of prison and is once again distributing his drug. Meanwhile, Moira goes on trial for her participation in the Undertaking. ADA Adam Donner (guest star Dylan Bruce) collapses in court with Vertigo symptoms so Laurel must step in and try the case against Moira. Oliver is torn between standing by his family during the trial and catching The Count. However, things change when Felicity follows a lead and walks straight into a trap set by The Count.

8. The Scientist

UK airdate: 9 December 2013

A seemingly impossible robbery at Queen Consolidated’s Applied Sciences Division brings Central City police scientist Barry Allen (guest star Grant Gustin) to town. Citing a similar case back home, Barry offers to help Oliver and team with the investigation. Oliver senses there is more to Barry than meets the eye, but he’s distracted by the similarities between this current case and something that happened on the island. Meanwhile, Felicity takes a liking to Barry, which doesn’t go unnoticed by Oliver. Sin (guest star Bex Taylor-Klaus) asks Roy for help when a friend of hers goes missing. Roy is surprised when Thea not only encourages him to help, but joins the search. Unfortunately, Sin’s friend is connected to Brother Blood (guest star Kevin Alejandro), and their search ultimately gets one of them seriously injured

9. Three Ghosts (Mid-season finale)

UK airdate: 16 December 2013

After a fight with Cyrus Gold AKA the Acolyte (guest star Graham Shiels), Oliver is drugged and left for dead. Determined to cure him, Felicity makes a risky decision. The cure causes Oliver to hallucinate, and what he sees forces him to confront his past. Meanwhile, Barry (guest star Grant Gustin) continues to help Felicity, and their connection grows stronger. The Arrow asks Lance to look into Gold, but when the stakeout on Gold goes bad, someone is killed. Roy is captured and tortured by Brother Blood (guest star Kevin Alejandro).

10. Blast Radius

UK airdate: 20 February 2014

Oliver must tackle a new threat to the city when bombs start to go off in Starling City. Felicity (Emily Bett Rickards) discovers the person setting them off is Mark Sheffner (guest star Sean Maher), a man who goes by the nickname Shrapnel. Arrow discovers Shrapnel’s next target is Sebastian Blood’s (guest star Kevin Alejandro) “Unity Rally” and tries to talk the alderman out of hosting it, but he refuses. Arrow sets off to stop the bombing, but Shrapnel tricks him and traps him in a bomb-laced antique store where he is unable to move without setting off the device. While Felicity helps Oliver, Diggle (David Ramsey) races to the plaza to find the bomb before it goes off. Meanwhile, Roy (Colton Haynes) continues to hide his new strength from Thea (Willa Holland) but, after she witnesses his super strength in action at the rally, she demands answers. Laurel’s (Katie Cassidy) suspicions about Sebastian grow stronger once she learns that he grew up with Cyrus Gold, the man who killed Lance’s (Paul Blackthorne) partner. After Donner (guest Star Dylan Bruce) refuses to help her investigate, she turns to Arrow (Stephen Amell) for help.

11. Blind Spot

UK airdate: 27 February 2014

Oliver (Stephen Amell) is conflicted after Laurel (Katie Cassidy) reaches out to the Arrow asking him to investigate Sebastian Blood (guest star Kevin Alejandro). Oliver is unsure whether to believe her accusations against the man he has publically supported for mayor, but decides to trust Laurel. However, when the pair gets too close to the truth, Sebastian exposes Laurel’s drug addiction and has her arrested. Meanwhile, Roy (Colton Haynes) reveals his new super-strength to Sin (guest star Bex Taylor-Klaus) who wants to test out his abilities. Unfortunately, Roy isn’t able to contain his rage once unleashed and almost kills a man. Back on the island, Oliver is surprised when Sarah (guest star Caity Lotz) reveals a secret about Laurel.

12. Tremors

UK airdate: 6 March 2014

Arrow (Stephen Amell) offers to train Roy (Colton Haynes) so he can learn to control his newfound super-strength. However, Roy is a rebellious student and refuses to listen unless Arrow reveals his true identity, which Oliver refuses to do. Meanwhile, the Bronze Tiger (guest star Michael Jai White) escapes from prison and steals Malcolm’s earthquake machine to sell to the highest bidder. Oliver, Diggle (David Ramsey) and Felicity (Emily Bett Rickards) attempt to stop the transfer, but Roy gets in the way, putting everyone in danger. Laurel (Katie Cassidy) is disbarred and spirals out of control. Moira (Susanna Thompson) is thrilled when Walter (guest star Colin Salmon) asks her to dinner, but his reason surprises her. Thea (Willa Holland) encourages her mother to ask Walter to reconcile.

13. Heir to the Demon

UK airdate: 13 March 2014

As Laurel (Katie Cassidy) continues to unravel, Oliver (Stephen Amell) and Lance (Paul Blackthorne) try to convince Sara (guest star Caity Lotz) to stay in Starling City and finally reunite with Laurel and Dinah (guest star Alex Kingston). However, Sara’s fellow League of Assassins member, Nyssa (guest star Katrina Law, “Spartacus”), comes to bring Sara back to the fold, but when Sara refuses, Nyssa kidnaps Dinah. Realizing she’s putting her family in danger by staying in town, Sara considers re-joining the league.

14. Time of Death

UK airdate: 20 March 2014

Oliver brings Sara into the Arrow team. Watching Oliver and Diggle spar with Sara and talk old scars, Felicity starts to feel left out. The team is investigating a villain named William Tockman, a.k.a. The Clock King (guest star Robert Knepper), who is a brilliant thief armed with technology that can open any bank vault in Starling City. After The Clock King infiltrates the computer systems in the lair, Felicity feels pressure to prove her worth. When she gets a lead on Tockman’s whereabouts, she heads out without the team, putting her in peril. Meanwhile, Oliver throws Sara a welcome home party, but Laurel refuses to attend. After Lance makes his case for a family dinner, Laurel acquiesces, but when Oliver shows up with Sara, she loses her temper on both of them.

15. The Promise

UK airdate: 27 March 2014

Oliver is shocked when he learns that Slade has come to Starling City. Back on the island, as Oliver, Slade and Sara prepare to take over the freighter from Ivo (guest star Dylan Neal), Sara pulls Oliver aside and tells him he needs to kill Ivo to prevent him from telling Slade what happened with Shado. Oliver feels immense guilt over the situation but realizes Slade’s growing rage from the Mirakuru makes him unpredictable and he could turn on his friends if he thinks Oliver is to blame. Oliver agrees to kill Ivo and the battle begins.

16. Suicide Squad

UK airdate: 3 April 2014

Following Slade’s return and his promise to make good on his threat to destroy Oliver’s loved ones, Oliver focuses all his energy on preparing for battle with his former friend. Sarah tries to help but, fearing for her safety, Oliver pushes her away. Meanwhile, Diggle is recruited by Amanda Waller (guest star Cynthia Addai-Robinson) and A.R.G.U.S. to stop a warlord (guest star Lee Majdoub) he knew from his time in Afghanistan. Always the solider, Diggle agrees to help. However, he’s not prepared when Amanda introduces him to the rest of the team – Deadshot (guest star Michael Rowe), Bronze Tiger (guest star Michael Jai White) and Shrapnel (guest star Sean Maher), all criminals he and Arrow helped put away. Lyla (guest star Audrey Marie Anderson) defends the team and explains the world is a complicated place, but Diggle isn’t sure he agrees. When the mission takes a dangerous turn, Diggle is forced to make a difficult decision.

17. Birds of Prey

UK airdate: 10 April 2014

When Frank Bertinelli (guest star Jeffrey Nordling) is arrested, Oliver knows it’s only a matter of time before his daughter, Helena, AKA The Huntress (guest star Jessica De Gouw), returns to town. To make matters worse, Laurel is picked to try Frank’s case, putting her right in the path of Helena. Oliver tells Sara he will handle his ex-girlfriend, but when Helena takes hostages at the courthouse, including Laurel, the Canary will stop at nothing to save her sister. When The Huntress and Canary meet, an epic battle begins. Meanwhile, Roy realizes he needs to keep Thea safe, but doesn’t like the way he is forced to go about it.

18. Deathstroke

UK airdate: 17 April 2014

Slade makes his move against Oliver and the repercussions are enormous. While Oliver scrambles to protect his family, a key player in his team starts to question Oliver’s decisions. Meanwhile, Isabel (guest star Summer Glau) makes her move to take Queen Consolidated away from Oliver.

19. The Man Under the Hood

UK airdate: 24 April 2014

Oliver, Canary, Diggle and Felicity return to the lair and find Slade waiting for them. An epic battle breaks out and one member of Team Arrow is sent to the hospital. Thea hits her breaking point, but just as Oliver is about to reach her, Slade intervenes and Oliver is faced with a choice – his battle with Slade or his family. Meanwhile, Laurel struggles with a new secret.

20. Seeing Red

The mirakuru sends Roy into an uncontrollable rage and he unleashes on the city. After Roy’s deadly fight with a police officer, Oliver realizes the mirakuru has taken over Roy completely and must figure out a way to stop him. Things get more complicated after Sara declares that Roy is too far gone and the only way to stop him is to kill him. Meanwhile, Thea believes she can breakthrough to Roy so she goes on camera at Moira’s campaign rally to lure him to Verdant. Her ploy works but after Roy attacks Thea, Team Arrow unleashes on him.

21. City of Blood

After Slade threatens to take everything Oliver loves away, Oliver decides the fastest way to stop further bloodshed is to surrender to his enemy. Knowing that surrender will surely lead to Oliver’s death, Diggle and Felicity go to extreme measures to keep Oliver from confronting Slade. Meanwhile, Thea (Willa Holland) considers leaving town, and Laurel resumes her crusade against Sebastian Blood (guest star Kevin Alejandro). Finally, Slade unleashes his assault on Starling City.

22. Streets of Fire

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 – Malcolm Merlyn (guest star John Barrowman).

23. Unthinkable (Finale)

Slade moves forward with his plan to kill one more person in Oliver’s life. While Oliver has fought all year to be more than the killer he once was, when Slade kidnaps someone close to Oliver’s heart, Oliver is pushed to the edge and realizes sometimes it takes doing the unthinkable to stop the monster. Meanwhile, Diggle takes on Amanda Waller (guest star Cynthia Addai-Robinson) with a little help from some friends, and Thea turns to Roy in her time of need.