The episode opens on a number of people picking up garbage on the shores of the bay during a Queen campaign event, when gunfire breaks out.
A toy helicopter is firing into the crowd, until Felicity takes control of it and crashes it into the bay. During the event, Oliver saves a child.
Back at the lair, Oliver says he's sure it's Darhk, while they watch a news report about people who are injured. The media wants a comment from Oliver, but he doesn't have one.
Meanwhile, Oliver says that they can un-brainwash Diggle's brother with enough time in the cage.
Back on Lian Yu, Oliver tells Taiana that he needs her expertise as a dive instructor to achieve his plan against Reiter.
In the present, Diggle shouts at Andy for abandoning his family, but Andy is not impressed. Diggle says Darhk attacked the bay today, and that he hurt a lot of people -- and that the drugs are now out of his system, so he shouldn't be in Darhk's thrall anymore. He says he wants to believe in his brother, and he asks Andy what Darhk wants with the bay. Andy says he doesn't know.
At the campaign office, Felicity meets her mother, who's decorating for the holiday party. Felicity excuses herself to go upstairs, but turns around when her mother screams: she's found Oliver's engagement ring.
At the bayfront, Oliver confers with Team Arrow and agrees to go on the air. Dozens of local and national outlets are there. He outs Damien Darhk and H.I.V.E. as the cause behind the attacks on Star City. He says for months, Darhk has made citizens afraid to walk the streets, and it's time to return the favor.
At H.I.V.E. headquarters, Darhk blows up the TV, seemingly with his mind, and an old man with a German accent tells him "Congratulations, Damien. You're famous."
At the lair, Felicity has holiday decorations. Oliver wants to cancel the holiday party, but everyone teams up on him to say that would send a message he's afraid of Darhk. Oliver tells them to talk to Lance about getting extra security.
Oliver asks Felicity whether they did the right thing, saying they know Darhk will retaliate. Felicity says that when he does, they'll be ready.
On Lian Yu, Oliver brings Taiana to the shore and gives her a map so that she can help him make a plan.
At her home, Thea meets Merlyn. He says that Darhk's effect on Thea has nothing to do with his involvement with the Lazarus Pit. He says he's afraid of the forces at play he doesn't understand and asks her to promise she'll be careful, which she does.
At the holiday party, Diggle has brought in a group of Marines for security. Curtis comes in and brings his husband. Felicity is awkward when she meets him, and pretty much reveals she knows about the ring. Felicity hears the story of their proposal and goes off to find her mother -- who is making out with Quentin. She's at first surprised and then grossed out -- and then she tells her mother that she's figured out he was going to propose three months ago.
Felicity realizes that things changed after they moved home. She asks him why, and he says he didn't change his mind, but he did need time to figure things out. She tells him ethat she can't understand why they can't have both the life they want.
Darhk and a battery of gunmen come in, and Darhk sweeps security's guns away with a wave of his hand. He tells Oliver that he wants to teach him a lesson by punishing the ones he cares about, and then he waves his hand and throws Oliver through a window. He tells his gunmen, "Take them."
Oliver wakes up at the campaign office, where Felicity's mother comes to tell him Felicity has been taken. He promises to get her back and stumbles back out. Alex says they took Thea too, and Lance says they have Diggle. Oliver tells Alex to get everyone medical help from the campaign funds, and heads out, telling Alex to stall the police, who want to talk to him. He heads out to the streets, where he starts cracking skulls looking for Darhk's location.
Back at the lair, Laurel tells him not to blame himself for this. He says he made the right call, and that Team Arrow can take care of themselves, including Felicity. Laurel gets a text from work, and Oliver heads back out to look for the ghost who's going to talk.
On the island, Oliver heads out into the water, leaving Taiana at the shore. He swims into the wreckage of the Amazo.
At the police department, Laurel comes to confront her father about working for Darhk. He tells her that Darhk threatened her and he did what he needed to do to keep her safe. She asks how many father's daughters have died because of him. Lance says he has been working for Oliver for a while -- and while they're arguing Oliver texts Lance to meet him now.
Both Lances go to the Lair. When Malcolm comes in, Lance points a gun at him and Merlyn taks the gun away. He has a phone that will work to contact Darhk, and reveals to Lance that he's the new Ra's. Oliver plans to turn himself over to Darhk.
At H.I.V.E., Damien is being criticized by the other board members, who aren't happy he's wasting time with Oliver. He gets the call from Ollie, though, and excuses himself. He meets Oliver at the bayfront, and Ollie says that he took his friends to make a point, and he's made it. Darhk says he hasn't yet.
At H.I.V.E., Oliver tells Damien to let his friends go. Darhk brings him into an area where he pontificates about the gas chamber. He brings a hollow-eyed man into the area, puts him into a gas chamber and kills him.
At the lair, Laurel is about to head out after Oliver. Lance wants to go, but Laurel tells him he has to let her decide whether she needs protection. He ultimately relents, but he tells her to be careful.
At H.I.V.E., Oliver is walking through some cells. Felicity sees him and calls out, so Damien gives him time alone with her. In her cell, Felicity objects to Ollie having made the decision to turn himself in for her, giving him a similar lecture to what Laurel just gave her father. She tells him that if he had proposed, she would have said yes.
Inside The Amazo, Oliver surfaces for air, then goes back down for a map squirreled away in a box. He takes another gulp of air and swims back to the shore.
In the main core of the H.I.V.E. facility, two ghosts grab Oliver and then they drag Felicity into the gas chamber. He tells Oliver that he's taking away his motivation by killing them. Oliver runs up to the glass and slams on it.
As Darhk is taunting him, Laurel and Merlyn show up -- Merlyn dressed as Green Arrow -- and Laurel uses her scream to shatter the glass. As Team Arrow makes an escape, Merlyn hangs back and shoots an exploding arrow at Darhk, who uses his mind to start strangling him. Oliver tackles Darhk before he can finish the job.
While Team Arrow are standing in the jail area, the other cells open and baddies start going after them. When the scream fails to take them all out, Lance shows up with a gun to help even the odds. Team Arrow takes down the prisoners, and then a group of cops join the fray.
Elsewhere, Darhk is beating on Oliver when Merlyn shoots him full of arrows, pinning him to the ground, and then leaves an explosive arrow next to him. Darhk recites an incantation, and the arrow explodes, taking out much of the building.
At the lair, Team Arrow is happy they took out Darhk, but Laurel doesn't believe he'll stay dead. Felicity and Thea apparently have a secret.
Oliver comes to the shore, wearing a shark bite scar, when Conklin and three other men come, catch him and Taiana together, and say they're going to "enjoy taking pieces out of you."
At the lair, Diggle tells his brother that he wants to believe in him, but Andy blows him off again.
The H.I.V.E. brain trust are unhappy with Darhk, but he says they're exactly where they need to be. He takes them out a door and into a corn field, where he tells them that using the algae that had created the gas chamber fumes, the air down here is "fully breathable." He shows them what looks like a huge, low ceiling, and they ask what about Queen.
At the second version of Oliver's holiday party, he makes an inspirational speech for the people in attendance and lights the Christmas tree, saying that they won't let terrorists win. He tells the crowd he's grateful for each of them, and then proposes to Felicity. She accepts, and the crowd applauds.
In a limousine later, Oliver and Felicity are sitting together. They kiss, and their car is cornered by a number of vehicles. Men walk out with guns and shoot the car up, while Oliver covers Felicity. Elsewhere, Darhk walks up behind a woman and her daughter as they trim a tree.
In the car, Oliver successfully takes control of the vehicle and drives away. Darhk hugs the little girl.
Oliver pulls over and checks on Felicity while Darhk, his apparent wife and daughter are decorating their tree together. He pulls Felicity out of the car, and she appears lifeless.