Grant Gustin does the traditional introductory monologue as Oliver.
During an Argus op, Diggle leads his team while Curtis watches from a van. The team is attacked by a heavily armored Joe Wilson, who is about to kill Dig when Supergirl, The Flash, and The Green Arrow show up and stop him.
Back at Argus, they explain their body swapping problem to Curtis and Diggle. When Felicity shows up to help, it becomes clear that Oliver didn't tell her about the swap and she believes Barry is Oliver.
As the three heroes get ready to head to Gotham, Oliver suggest Barry remain behind, since Oliver Queen's fame will make things difficult. Barry counters by reminding Ollie to keep the mask on as The Flash. They also argue about Batman, who Ollie insists is a myth.
Kara finally settles things by grabbing Barry and flying to Gotham. They land on a rooftop and are soon joined by Oliver, who continues to struggle with his speedster abilities. They discuss how to find the people from Cisco's vibe, and Oliver mentions knowing a local reporter. He's not sure she will help though, as he can't remember if he slept with her. They find The Bat Signal on the roof, though Ollie continues to call Batman a myth. Batwoman watches them from the roof of Wayne Enterprises.
In their civilian clothes, the heroes walk towards the radio station where Ollie's reporter contact works. They see a couple shopping with an armed guard and discuss how crime ridden Gotham City is. As if on cue, a gang of thugs walk up and attempt to mug them at gunpoint. Ollie tries to talk them down but is quickly in over his head and Barry fights, taking it way too far. The cops arrive, recognize Barry as Oliver, and arrest everyone.
Felicity and Curtis work at Argus, trying to find a pattern with the red lightning storms they have noticed. They realize it is consistent with a breach and need Cisco. Luckily, Cisco realized the same thing and arrives at Argus with Caitlin immediately. Caitlin accidentally reveals to Felicity that Ollie and Barry have switched bodies.
In jail, Kara is fed up with Barry and Ollie bickering and calls them both out for how the handled the mugging, pointing out she could have gotten them away so fast they wouldn't have been seen. Ollie concedes that she should be in charge next time. Their bail is posted and the three are released.
Outside a man meets them. They realize he works for the person who bailed them out and when he shows then a gun, they go with him.
He drops them off at Bruce Wayne's home, which was nice once, but not anymore. Inside they are greeted by a tattooed woman who recognizes Barry and Ollie for who they are. She is Kate Kane and she wants them to leave her city as soon as possible.
Caitlin and Cisco are mad at Diggle and Curtis for hiding the truth from Felicity. Felicity is mostly upset that Iris recognized her husband while Felicity didn't. But she says they need to focus on the lightning instead.
On the roof, Kate talks to Kara and Ollie. Kara asks why Bruce Wayne and Batman both went missing at the same time – three years ago. Kate says Bruce couldn't live with what Gotham became after Batman left.
Barry shows up, Ollie's contact won't help. Kate gives them the wifi password and heads inside to work while Ollie reveals he stole police data.
Caitlin talks to Felicity, pointing out that Iris has a lot more experience with alternate realities and that would have made her more open to the body swap. Felicity doesn't think Ollie respects her, but Caitlin encourages her. Felicity meanwhile has plans for a quantum flux anchor to help open the breach.
Oliver searches facial recognition and finds out about John Deegan. He experimented on his patients, but was acquitted due to technicalities. He can't find Deegan's current address or employment. Kara decides to search the city.
Inside the building, Kara sees Kate and reaches out to her. Kate explains that she is Bruce's cousin. Kara says her own cousin is frenimies with Kate's. They talk and Kate flirts a little. Kate knows John Deegan and says he works at Arkham Asylum.
Kate heads down to the Bat Cave, where she keeps the Batwoman suit and wig.
Curtis, Diggle, Felicity, and Caitlin set up Felicity's quantum flux anchor while Cisco handles the computers inside. There's multiple surges, and a breach almost opens, with the John Wesley Shipp Flash peering through, Caitlin calls him Jay, but he ignores her and tells them to get the book before the breach closes again.
Outside of Arkham, Kara, Oliver, and Barry discuss how to break in. Cisco breaches through with Diggle to pass the message.
Kara pushes Caitlin in a wheelchair and tells the administrator that she is delivering a new patient from the hospital, using Killer Frost's powers to bolster the lie. Meanwhile, Ollie uses Barry's CCPD credentials and Diggle uses his Argus ones to bully their way into an inspection. They walk down the hall, where several familiar names are on the patient doors, before they find Deegan's lab.
Deegan recognizes Oliver for who he is, and pushes a button which triggers an alarm and releases all the patients so he can escape.
Diggle, The Flash, Supergirl, Killer Frost, and The Green Arrow help recapture the patients. When a few almost get away, Batwoman shows up and stops them.
Meanwhile, Killer Frost is facing off with Nora Fries, who has some of her husband's cold technology. Killer Frist calls for help and both The Green Arrow and The Flash hurry to assist her.
Deegan grabs the book from a hiding place inside the walls, but is found by Supergirl who takes the book.
The Green Arrow and The Flash show up and find Killer Frost knocked out. The Flash throws a lightning punch, but Oliver still does not have a handle on these powers and he knocks over several vials labeled 'Crane' which spill and release a gas into the air.
In front of Barry, Malcolm Merlyn appears and addresses him as Oliver. In front of Ollie, the Reverse Flash (as Harrison Wells) appears and taunts him like Barry. They fight each other's arch nemesis but when Caitlin comes to as herself, she realizes they are fighting each other.
Barry and Oliver continue to fight as they hallucinate themselves being taunted. Batwoman appears and stops them, recognizing the vials and explaining they were exposed to a serious hallucinogen.
Batwoman kicks them all out of her city. Supergirl stays behind and reveals she is Kara, and due to her x-ray vision she knows Kate is Batwoman. They share a moment of solidarity.
The book is now at Argus, and Felicity is eager to translate the cryptographs inside. Barry and Oliver talk about their hallucinations and acknowledges each other's burdens. Barry encourages Ollie not to wait to talk with Felicity.
Ollie sits with Felicity and tells her they will be okay. Recent events have shown him that they might change as people, but he will always love her no matter what and they make up.
Finally, the other Flash is able to breach into Argus. He is not Jay Garrick though. He is Barry Allen, from Earth-90 which was destroyed by The Monitor – the other man in Cisco's vibe. He uses The Book of Destiny throughout the multiverse.
The Monitor is in the street. Supergirl, The Green Arrow, and both Flashes confront him. The O.G. Flash heads towards The Monitor who makes him vanish. The Monitor says he is trying to save the multiverse from a crisis. He summons the book from Argus and disappears.
Deegan is crying when The Monito appears before him and hands the book back over, telling Deegan to think bigger and do better.
Suddenly, Barry and Oliver realize they are dressed identically, and a newspaper headline says they are wanted criminals known as The Trigger Twins. Kara is nowhere to be seen and neither of them is a speedster. A cop car pulls up and three police officers emerge. Joe Wilson, Malcolm Merlyn, and Ricardo Diaz. Diaz starts to arrest Oliver, who fights back and he and Barry run. Only to be stopped by a version of Superman who is dressed all in black.1comments