Lex Luthor is considering the box that contains Brainiac's essence and complaining about how he has to acknowledge Grodd's leadership as a price to pay. Tala attempts to comfort him without success and Lex prepares to obtain the Brainiac AI using his equipment. He doesn't have any success and wonders if Grodd is thwarting his efforts. He goes to see the imprisoned Grodd and demand the answer, and Grodd notes he has no reason to give up his only bargaining chip. Tala suggests they break open Grodd's head and take the information, giving Lex an idea.
The villains confront Lex and demand more aggressive leadership, asking why they should follow him. Lex offers to show them more money in one day then they've ever made in their lives.
Aboard the Watchtower, the heroes discuss how to track down Grodd's new secret society of villains. Mr. Terrific suggests they take advantage of the mental link that Grodd once established with Flash to track down the gorilla. Dr. Fate can track the essence to the villains' lair. Flash isn't comfortable with the idea but Dr. Fate assures him that he won't invade his privacy. Flash finally gives in and Dr. Fate begins the spell. At the same time, Lex prepares to mentally scan Grodd's brain by hooking up his own brain. Aboard the Watchtower, Dr. Fate starts to trace into Grodd's mental signature but Flash's brainwaves cross with Lex's. The two of them scream in pain and Flash collapses to the floor. Dr. Fate warns that it's Lex Luthor's mind in Flash's body. Lex-in-Flash runs away at superspeed and the other heroes are unable to restrain him for long. He threatens to kill one of the Watchtower technicians unless they teleport him to Earth but Mr. Terrific knocks him away with one of his T-Spheres, blowing up the teleporter. As Lex-in-Flash runs past the security doors, Green Lantern wonders what's happened to Flash's mind.
In the secret society headquarters, Flash wakes up to find himself surrounded by puzzled villains. He tries to run out of the chamber but quickly finds himself exhausted. He soon figures out that he's in Lex's body.
Aboard the Watchtower, Mr. Terrific sends out the security alert but Lex-in-Flash has already subdued many of the heroes. Green Lantern and Dr. Fate home in on the Flash's ID badge inside of a storeroom. They find the badge, abandoned, and figure it's a trick. The remaining heroes cover the escape routes while Dr. Fate meditates to come up with a new spell.
In the society headquarters, Tala approaches Flash-in-Lex and warns him not to show weakness. A confused Flash-in-Lex runs into the men's bathroom and finds a mirror. He tries to call out on his cell phone but doesn't get service. As he leaves, Dr. Polaris demands to know when they're going to go over their plan. Flash-in-Lex covers as best he can.
Lex-in-Flash tries to get past the security doors when Green Lantern and Red Tornado attack. He knocks them back and attempts to vibrate the door open. He succeeds and gets to the Javelin bay, then takes a Javelin and tries to blast his way out. The weapons won't work within the bay, so he starts ramming the Javelin into the doors. Green Lantern cuts open the hull and Lex-in-Flash generates a tornado. Green Lantern goes after his friend's body while Red Tornado counters the tornado with his own.
Flash-in-Lex addresses the assembled villains but they begin to realize something's going on. Flash-in-Lex questions the villains and attempts to get them to explain what Lex told them earlier. They'll be attacking a currency train in Kasnia transporting new funds. Satisfied, Flash-as-Lex makes a hasty exit and Tala gets him into their private quarters.
Lex-in-Flash takes cover in a restroom and unmasks, only to discover he has no idea who the Flash's secret identity is. Back in the society headquarters, Tala is pleased with "Lex''s" new personality. Flash-as-Lex tries to get to a communication room but the villains are ready to go on the heist. A soldier arrives to inform Flash-as-Lex that Grodd wants to talk to him. Flash-as-Lex goes to see him and Grodd reveals that he knows what happened because his mind was in the circuit when the transfer occurred. Grodd isn't interested in helping Flash to get revenge on Lex, but figures it'll be more entertaining to watch Flash-as-Lex twist in the wind. Tala comes in and Grodd comments on their former relationship, but Tala says Lex is her man now.
Dr. Fate comes up with the necessary spell but needs physical contact with at least one of them. Green Lantern and Red Tornado have cornered Lex-in-Flash in the cafeteria but he's still too fast for them. Dr. Fate arrives and temporarily immobilizes him, but Lex-in-Flash stuns him with a few hundred superspeed punches and throws cutlery, plates, and food at the other two. He manages to throw a bowl fast enough to penetrate Green Lantern's shield, stunning him.
The villains close in on the Kasnian train and Lex has no choice but to order the plan into motion. Sinestro and Dr. Polaris take out the helicopters and destroy the bridge, and the train goes off the tracks to where Sinestro redirects it to a nearby train. They take the currency out of the crates while Flash-in-Lex ties up the guards. Unfortunately, Lex-in-Flash gets to a communication board on the Watchtower and notifies them that Flash-in-Lex is an imposter. Dr. Polaris asks him what his real name is and when Flash-in-Lex fails the test, he tries to send an emergency message. Mr. Terrific gets the coordinates and sends a team down. Meanwhile, Green Lantern is decoyed away while Lex-in-Flash gets to the bridge, knocks out Mr. Terrific, and reassembles the teleporter at superspeed.
In Kasnia, Steel, Dr. Light, and Ice find the cave and disable the villains' transport. Tala opens a portal and Dr. Polaris takes magnetic control of Steel, buying time for their escape. Aboard the Watchtower, Lex-in-Flash completes the repairs as Mr. Terrific recovers conscious and shuts off the artificial gravity. Lex-in-Flash drifts into the air and tries to redirect himself, but Mr. Terrific restores the gravity and Lex-in-Flash slams into the ground, unconscious. Dr. Fate casts his new spell and the two individuals are back in their correct bodies. Unfortunately, Flash has no idea where the headquarters was.
In the society headquarters, the villains beat up Lex (in his correct body) and Dr. Polaris isn't convinced or particularly concerned. He prepares to kill Lex, but Lex activates a belt device overriding Polaris' abilities. Satisfied, the villains back down while Tala is disappointed that the "old" Lex is back.