This article contains spoilers for Arrow season 6, episode 18, 'Fundamentals'.
This episode kicks off with a lot of action as Oliver (Stephen Amell), in his season 1 costume, goes into police headquarters after Ricardo Diaz (Kirk Acevedo) and is being pretty brutal to anyone in his way. Sure these are cops on the take, but they're still cops. He mows through six or eight and then is about to open a door where Diaz is supposed to be, and we see on the other side Diaz is standing there with a dozen armed cops ready to go.
Then we get the opening credits and jump back 10 hours and we see Oliver and Felicity (Emily Bett Rickards) watching the news coverage of Oliver being accused of obstructing justice. Felicity tricks Diggle (David Ramsey) to coming by on false pretenses to try and patch things up and show that Diaz goes to the police station every night at the same time. Diggle and Oliver do not make up.
Oliver goes to a meeting in the Mayors office where Councilmen Kullens (Greg Rogers) is telling Oliver that the Council is meeting to decide about impeaching him based on him firing the D.A. and police captain. Oliver says he'll be there with evidence of their guilt. He talks with Quentin (Paul Blackthorne) after the meeting and admits he doesn't have the evidence yet and he's counting on Felicity. He also tells Quentin that Diggle left what used to be a team. Quentin tries to be supportive. Oliver has to take William (Jack Moore) to a science fair that morning.
Back at the apartment, we see Raisa (Kathleen Gati) is there and William is excited about his science project. Oliver comes home and Felicity has the evidence, but it will be impossible to use as it could only come from the Green Arrow. He pushes her for more answers while William complains they will be late. Oliver gets mad and accidentally breaks Williams science project. Felicity tells Oliver to get out. Oliver goes to the bunker to think, where he hears a weird knocking, then Felicity arrives to tell him that they need some space.
Things keep getting worse for Oliver, who turns to Quentin, giving him the evidence they have and asking why everyone keep leaving him. Quentin tries to console him and suggests things will work out with Felicity. He also suggests using Agent Watson as a way to bring the evidence in and is going to call her. Quentin leaves, and Oliver starts hearing the knocking again. He grabs a gun and then hears the elevator. The doors open to reveal Adrian Chase (Josh Segarra), who reminds Oliver he never went back for the body. Oliver is shot and then they fight. After throwing each other around the Bunker, Oliver gets Adrian in a headlock. Adrian tells him he's just going to keep coming and will kill Felicity and William. Oliver breaks Adrian's neck and leaves him for dead. But when he looks back, there is no body and Oliver isn't shot.
Oliver realizes that he is hallucinating and runs a blood test on himself. Adrian returns as he's doing it. When it shows Vertigo in his system, Oliver realizes he was drugged by Kullens and wants to talk to Quentin, but Adrian tells him that's bad idea. He gets a call from Lance and finds out he's late and that Watson is still deciding if she'll help. He tells Quentin that he's been dosed and that Diaz has been dealing with Vertigo. Adrian tells him that all the villains that have tried to take Oliver down come in second, as Oliver is his own worst enemy.
Oliver heads to the office but winds up in his old living room in the mansion the night before they left on the Queen's Gambit. He sees Laurel (Katie Cassidy), who is obviously in love with him. From there he's in his current apartment and finds Raisa stabbed on the couch and Diaz there, hitting him with a taser and talking about tearing him down. He then ends up back in the Bunker where he is confronted by The Hood, who tells him he has failed the city because he has lost sight of his mission. That there was never supposed to be a team or family to lose… just the mission.
Oliver gets to the meeting an hour late. Watson won't help, so Oliver presents the evidence as coming from the Green Arrow. He seems a bit erratic, so Quentin gets him out of there and tells the council that there is a family emergency. Quentin leaves him to go back to the Bunker. The Adrian hallucination returns, reminding Oliver the only way to make this stop is to get Diaz, and that he'll be at the police station that night.
Back at the apartment, Felicity and William return from the science fair and an alarm goes off showing that Oliver is headed to the police station. Felicity calls Quentin and he tries to stop Oliver, who is in the original Hood version of the suit, but Oliver decks him and goes in anyway… and we're caught up from the opening scene.
Felicity arrives and checks on Quentin before going in after Oliver. She catches him before he opens the door and shows him how many heat signatures are on the other side. He reminds her that she left, but she says she never did… the Felicity in the Bunker was another hallucination. She wouldn't leave him. She convinces him to get out of there just before Diaz gets tired of waiting and sends the cops out after Oliver.
Back at the Bunker, Felicity gives Oliver a drink to help counter the Vertigo and Oliver apologizes to Lance for punching him. Oliver tells Felicity that the hallucinations gave him clarity and that he needs to get back to basics — back to when it was just him out there. Quentin comes back in and turns on the TV to see that Oliver has been impeached, which interestingly makes Quentin the new Mayor of Star City.
Back at the apartment, Felicity is not happy about being fired as Overwatch, and Oliver says they'll talk about it more but he needs to see William. The conversation goes well as William heard that Oliver had been drugged and things seem fine there. We end at police headquarters as they are cleaning up from the Hood attack. Laurel-2 walks in and Diaz is sitting at the Captain's desk. She asks him why he didn't just kill Oliver. Diaz explains that Oliver would be a powerful martyr, but tearing him down bit by bit prevents that.
The episode was very interesting in that it brought up a lot of thing going on in Oliver's head. This is the episode that Amell said he was in almost every scene, and now we see why. There has been some folks acting a bit out of character this season, but Felicity leaving Oliver for him getting upset seemed a bit far. Yes, it was a bad situation, but I don't see her giving up on him until every possible option is tried… so it being a hallucination makes sense. But there is bound to be some fallout from him going solo again.
Oliver not being the mayor could be a blessing, allowing him to focus again, which is something Diggle was complaining about. And having Quentin as Mayor could be a good thing. Not sure how they'll end the season, but that is an interesting dynamic.
Next week Diaz has declared Star City open for business.