Karen convinces the other Synths that she wants to keep them safe, but their ideas on what that means is vastly different.
Hobb’s men look through the Hawkins’ house. The officers take their cell phones and Laura says that she is going to make a formal complaint to the commanding officer.
Pete drives up to the Hawkins’ house. He asks the police commissioner to speak with Hobb. The Commissioner says a million people are coming to London to protest Synthetics for the We Are People march and tells Pete to make himself useful.
Pete walks into the Hawkins’ home. The Commissioner explains to Laura that Hobb’s men will destroy the Synths. The Commissioner tells Laura they have a good life and they shouldn’t risk it. Pete overhears this.
Laura tells the family to go upstairs. Laura explains that if they can bring proof to the public, they could use it for leverage. Mattie explains that she could use the copies of Leo’s memories as the leverage.
At the lab, Leo tells the other Synths to make the connection so they can save Max. The Synths link their minds. Outside the room, Hobb watches the code form an executable file on the computer the Synths are linked to. However, the Synths are surprised when the file doesn’t work. Mia suspects it’s because not all of the sentient Synths are present.
The executives ask Hobb why he didn’t kill Fred, even though he showed them the burned body. A technician wheels an unconscious Fred into the room. Hobb explains that people don’t just want to be served; they want to be loved. He says he wants to build on David’s work, except his Synthetics will be obedient. Hobb turns Fred on and Fred immediately lunges for Hobb’s throat, but can’t make contact with him. Hobb explains that Fred’s code obligates him to be loyal to Hobb. “You would trap us in our own minds? Give us feeling but take away free will?” Fred says. The executives ask what will happen to the rest of the Synths. Hobb says he has David’s file now, so he’ll recycle the rest for their hardware.
Mattie and Toby attempt to leave the house but Pete barges in. Laura explains they’re trying to save the Synths. Pete says he wants answers. Pete leads the kids past the officers outside. Mattie reclaims her laptop from the police van and they drive away in Pete’s car. Laura tells the Commissioner she wants to speak to Hobb immediately.
Alone and strapped to a chair, Leo tells Hobb he wants to go with the other Synths. Leo says Hobb can’t just keep him there. Hobb muses that Leo is not entirely human so his rights are in a gray area.
Meanwhile, lab technicians prepare to destroy the Synths. They decide to start with Mia.
Leo sits in a white cell when Karen walks in. He asks her why she betrayed them. She says she’s fixing David Elster’s mistake. He asks her to join with them so they can save Max’s mind and unlock the secret. He tells her that she’s one of them, but she walks out of the room.
Mattie plays back Leo’s digitized memories on her laptop. She sends stills of the video files to Laura.
Hobb walks into the Hawkins home. Laura explains they will bring copies of Leo’s memories to the press. Laura shows him stills from the memories featuring David Elster and the other Synths. “They’ll lead with that on the news tonight, don’t you think?” she tells him. Hobb calls the lab technicians to cease the destruction of Mia. He says they’re letting the Synths go.
The Synths are freed and reunite with Leo. Mia receives a phone call from Laura, who tells Mia where to meet them.
Karen sees the Synths leaving through the glass in the lab. She asks the lab technician where they’re going; he explains they’ll be back because Hobb has a failsafe. The technician replays some of Leo’s memories on the computer. Karen asks how far back it can go. He shows her one of Leo’s most-played memories featuring Beatrice smiling at Leo.
Laura messages Mattie that the Synths are safe at the rendezvous point. As Mattie puts her computer away, Pete says he’ll give it to Hobb.
Fred surreptitiously transmits the Synths position to Hobb and his team.
Police close in on the Synths’ and the Hawkins’ position. They flee to a church and hide in a crowd assembled for the We Are People march. When Leo wonders how they could have found their location, Toby says Fred was acting strange. Leo walks over to Fred but Fred immediately twists his arm. The other Synths overpower him and shut him off.
Leo calls Hobb to say they know what he did to Fred. Hobb says it doesn’t matter because he has David Elster’s code. Leo says the code isn’t complete. Leo asks to talk to Karen. He tells her to come with them and tells her where to find them.
Pete arrives at Hobb’s facility but sees Karen walking away. He gives the laptop to one of Hobb’s men and follows her.
The Synths and the Hawkins wait in the church. Joe tells Laura she’s done everything she could to keep them safe. “Why is it your job to keep everyone safe?” he says to her. “Because of Tom,” she says. She shows him a picture of her deceased younger brother. Joe is upset that Laura kept it to herself for so long.
Leo examines Fred’s code to try to isolate Hobb’s programming. Leo says that it’s been built directly into the root code and can’t be removed. Karen arrives at the church. Leo tells the other Synths they need her to save Max.
The Synths all connect their minds through Leo. One by one, they enter the mindscape and put their hands on a large tree.
Suddenly, each of the Synths are overcome with their most traumatic memories and their eyes turn white. In the real world, Mattie explains that the code is corrupting. “It’s like one of them is infecting the others,” Mattie says.
Mia holds Leo, who is almost unconscious. She looks up at Karen. “Why are you doing this?” Mia asks. Karen says that if she helps them, they’ll create millions of new, young minds wanting the freedom that humans will never give. Mia tells Karen that if she destroys their minds, Leo will die too. Mia says that Karen is her sister.
Karen puts her hand to the tree. Mia does as well.
In the real world, the code corrects itself and completes. The Synths and Leo wake up. Max opens his eyes too. “We’re all together,” he says. Joe hurries to turn Fred off. “You have to leave me!” he shouts before Niska turns him off. Mattie asks what they’re going to do with the completed consciousness file. While they discuss it, Karen walks away.
Niska puts the file on a hard drive and she hands it to Laura. She says it belongs with someone they can trust. The Synths prepare to leave, but they can’t take Fred with them. They keep him turned off in the corner of the church and put a cloth over him. When Leo says it’s time to go, Niska says she wants to live her own life. She hugs Mia, Max and Leo and walks out of the church alone.
Before they leave, Mia hugs Laura and Sophie. Then she leaves with Leo and Max.
Karen walks down the street and Pete calls out to her. He asks how she got her scar. She says she did it herself for misdirection. “You figured it all out without my help. You’re really blossoming,” she says to him. He asks her if she’s coming with him. They walk away together.
Back at home, Laura puts the hard drive in her closet. Mattie says she can’t find her flash drive.
On a train, Niska holds the flash drive in her hands.