Evening in Central City, and homeless people move through the alleys. A shadowy figure offers one man on his own, Jack, a large bill.
Three of the homeless, including Sam and Charlie, hear a scream. They go over to investigate and find the homeless man staggers out, his face disfigured. He cries to Charlie and collapses, and they realize that it's their friend Jack. They hail down a patrol car but when they come back, they discover that Jack's body is gone.
At the station, Barry is walking out when Father Michael spots him and comes over to shake his hand. Michael says that there have been problems with homeless people on the streets, and they're waiting to talk to Garfield. The priest explains that several people in his parish have vanished. Barry takes him to Garfield, who says that the homeless have often deliberately disappeared and have no ID, and he can't assign more officers until a body turns up. Once Michael leaves, Garfield tells Barry that he doesn't have enough manpower to cover skid row and tells Barry to stick to his lab.
Tina is attending a presentation by Dr. Carl Tanner, who talks about the benefits of genetic modification. Barry comes in late and Tina waves him over. Carl talks about holding the future in their hands, and everyone applauds. Afterward, Carl sees Tina and comes over to hug his old friend. She introduces Barry, and she and Tina stares at each other. Carl says that he's in town for the next year, and Barry suggests that Carl try his knowledge of genetics. Barry jokingly tries to keep up, and notes that his research raises moral questions. Carl dismisses himself as only a scientist, but Barry says that they should be responsible. Tina pleads an early work day and Carl offers to drive her home.
Outside, Tina tells Carl to be careful with his work. She warns that her husband David was working on genetic research and it killed him, and Carl assures her that he'll be fine. Sam comes up and asks for spare change, and Carl gives him $20. Once Sam leaves, Carl tells Tina that seeing a human life wasted angers him and she tells him that he can't make that judgment. They arrive at Tina's house and Carl asks if they would have had a chance if Tina hadn't gone to Tokyo with David. He kisses her, and Tina abruptly goes into her house and looks at a photo of David.
The next day at the station, Julio brings the mail to Barry. There's a postcard from Iris saying that she's doing well in Paris. Julio tells Barry that she's not coming back and Barry should move on, and burns the postcard. He points out that Barry went out with Tina, and Barry says that Carl was Tina's old flame. Barry insists that he and Tina are just friends.
Out in the lobby, homeless people are banging on the cage window and demand justice. Michael tries to calm them down, saying that they just came to talk. As Barry and Julio arrive, the officers push the homeless back. One man, Mickey, grabs a gun from an officer and panics, and the officers draw their guns on him. Barry disarms Mickey invisibly at superspeed, and Garfield agrees to release Mickey to Michael as long as he gets the homeless out of the station. Barry offers to take the priest and a couple men up to the lab to help them out, and Garfield irritably agrees.
Up in the lab, Michael has Sam and Charlie tell Barry and Julio what happened. They insist that someone is killing homeless people and taking the bodies, and describe how Jack was transformed. Sam then reluctantly says that there are stories of someone prowling around, offering homeless people money, and then sticking them with money. Barry offers to go down and check it out, and Michael gives him the address. As he goes, Barry says that he thinks Charlie looks family. Charlie tells him that they don't hang around with the same crowd and leaves.
That night, Sam goes into an alley and a man follows him. Sam spots the man and grabs him, and realizes that it's Barry. Barry has groceries and Sam takes him to the other homeless people... while another figure watches them.
Sam hands out the groceries and tells Barry that they need an act of God. Barry asks where he's from, and Sam puts him off.
The figure with a syringe gun injects Charlie and then takes out a pocket watch. Charlie's hand transforms and he screams in pain. Sam and Barry hear him, and Barry turns into Flash and speeds to the alley. He finds a disfigured Charlie screaming in pain and watches as he dies, while the figure--Carl--watches Flash check the body.
The next day at the morgue, Barry talks to Dr. Mortimer. Mortimer takes out the body and shows that there's no sign of disfigurement. The autopsy shows that Charlie died of heart failure, and Mortimer agrees to send a blood sample to the lab. Michael and Charlie come in to identify the body and Charlie sarcastically thanks Barry for his help.
At the lab, Barry shows Julio a yearbook and Julio laughs at Barry's high school photo. Barry points out a photo of Charles Wright and Julio confirms that it's Charlie. Julio has the blood sample and Barry tells him to run every test on it that he can.
Barry goes downtown and talks to Michael, who says that Charlie needs a job and a place to live. The lab scientist then approaches Charlie and says that he's found him a night watchman job and an apartment. Charlie insists that he has his pride, and Barry suggests that he has too much pride. The homeless man says that they barely knew each other in school, and worries that he'll screw up. Charlie gives in and takes his job at STAR Lab, and thanks Barry for his help before he leaves. Barry then suggests that Tina join him for dinner, but she says that she invited Carl to dinner and leaves.
At Tina's home, Tina and Carl have dinner and Carl talks about Flash. Tina dismisses it as wild rumors and a bogus newspaper story. She talks about how she and David rebuilt the house, and Carl asks what happened to David's notes about genetic reorganization. Tina says that she has them at the lab but doesn't want him to see them, because the same research killed David. Carl drops the matter and apologizes for upsetting her, and Tina suggests that they go inside for dessert. She goes on ahead and Carl secretly drugs Tina's wine before giving it to her.
At the lab, Julio tells Barry that the tests on the blood changed every time he ran them. Barry suggests that they use the equipment at STAR Lab to analyze the sample. He calls Tina, who has passed out from the drug. Carl captures her retina print with a device and then wakes her up once the phone stops ringing. He tells her that she's been working too hard and fell asleep, and excuses himself. He goes to STAR Labs and uses Tina's eye image to get past the security.
Barry calls Charlie at STAR Labs and asks if Tina is there. Charlie says that she left hours ago. An alarm goes off as Carl breaks into the cabinet with David's notes. Charlie hangs up on Barry and goes to investigate. Carl has found David's journal and copied the pages.
Flash speeds to STAR Labs.
Charlie enters Tina's lab and Carl clubs him over the head. Flash arrives a few seconds later and sees Charlie in the vacuum chamber. He goes in to check his friend, and Carl seals the door and turns on the vacuum pump. As the oxygen runs out, Flash uses the star badge Charlie is wearing to cut a hole in the glass at superspeed. The speedster shields Charlie as the glass rushes in. The police take Charlie away and Tina confirms that he'll be okay. She tells Barry that there's nothing missing, and Barry blames himself for what happened to Charlie. Tina notices a page in the copier and realizes that it's from David's journal and takes it to Barry.
Carl is working in his university chemistry lab and using David's notes to prepare a new formula and put it in his hypo gun. He then injects it into a test dog and times the reaction. The dog goes berserk, mutating into a humanoid form, breaks out of its cage, and leaps through the window.
Barry figures that Carl is the thief, but Tina doesn't believe it. He insists that Carl is using her, and Tina wonders if he's jealous. They argue and agree that they should dissolve their "partnership", and Barry walks out.
Bellows and Murphy search the streets for the mutant, figuring that it's a rabid dog. They hear something in an alleyway, and see the shadow of the mutant creature. Bellows goes after it alone and Barry, driving nearby, hears Murphy's report on the radio. The creature advances on Bellows, and Flash arrives and gets him out of the way as the beast charges. As Barry and Murphy arrive, the creature transforms back into a dog.
Barry takes the dog to STAR Labs and Tina confirms that its cells are mutating. She says that it was the research David was working on before she died, and admits that Carl used her. Barry tells her that he has to stop Carl and speeds off to confront Carl.
At his lab, Carl makes more of the serum and prepares to inject another animal. Flash arrives and tells Carl that it's over. Carl refuses and picks up a bottle of explosive hydrazine, and throws it at the wall. Flash catches it and Carl locks himself in the closet and injects himself with the serum. He screams in pain as he transforms, and then bursts out and knocks Flash across the room.
Murphy and Bellows are patrolling the streets. . The transformed Tanner flips their car over and prepares to smash them with a mailbox. However, he clutches at his chest and drops the mailbox , and starts transforming back. Bellows sees it and crosses himself as Carl staggers off,.
Carl goes to STAR Labs and asks Tina for his help. He insists that he had to kill the homeless people, and says that their lives are worthless and his real parents were also homeless. Carl explains that he pretended to be rich, and says that homeless people should be cleaned off the streets. He insists that the serum needs to be ionized per David's notes. When Tina tries to interfere, Carl knocks her unconscious.
Flash wakes up and calls STAR Labs, but Carl has tied Tina up and injects himself with more of the serum. Tina warns him that he doesn't know what he's doing and if he cares about her, he'll stop. Carl prepares to inject her as well, but Flash speeds in and takes the hypo gun away. He unties Tina, but Carl manages to grab him by the throat and throws him away. The transformed Carl breaks through the door and runs out, and Tina goes to Flash.
Carl rampages through the homeless district, attacking any homeless people that he finds. As he advances on a woman, Flash whisks her away and goes back. He avoids Carl's blows and punches him repeatedly as the homeless people watch and cheer, and then wraps Carl up in wire fencing. Carl transforms back to normal and collapses, and Tina runs over as Flash speeds off. Barry returns and hugs Tina as the police arrive.
Written by Gadfly on Dec 8, 2018