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.

Team Green Arrow's ongoing battle with Damien Darhk is complicated by a shocking revelation. Thea's bloodlust returns and she loses control in front of Alex.

After the city is attacked again, Oliver makes a bold move against HIVE. Malcolm checks in on Thea and leaves her with a warning. Things take a horrible turn when Damien Darhk retaliates in a brutal manner at Oliver’s mayoral holiday party.

Oliver must deal with the devastating consequences of Darhk’s last attack. Seeking revenge, Oliver goes on a brutal manhunt looking for Dahrk.

Diggle must learn to trust his brother Andy when an enemy of their wartime past, an agent of the criminal organization Shadowspire, pays a visit to Star City. However, Diggle learns more than he bargained for about their shared time at war. Meanwhile, Oliver has to learn a whole new way of life.

Brie Larvan breaks out of jail and turns up at Palmer Tech threatening to kill everyone unless she gets the bio-chip that is implanted in Felicity’s spine. When Oliver realizes that Felicity, Thea and Donna are trapped in Palmer Tech with everyone else, he looks to a surprising ally to help Team Arrow save the day.

Oliver and Diggle learn that Merlyn is going to try to break Darhk out of prison. Meanwhile, Laurel gets a surprising offer and Felicity has a heart-to-heart talk with Curtis.

Oliver and the team struggle to come to terms with Laurel’s death, especially Diggle who is overwhelmed with guilt for choosing to believe Andy had changed. Meanwhile, Lance refuses to believe his daughter is really gone and asks Nyssa to help bring her back. A recent Black Canary sighting in Star City only seems to prove his theory that Laurel isn’t actually dead.

As Oliver and Felicity look for a magical solution to defeat Darhk, a vengeance-driven Diggle gets a lead on Andy’s whereabouts and heads off to confront his brother. Meanwhile, Alex takes Thea on a vacation that quickly turns into a nightmare.