At the hideout, Leo begs Mattie Hawkins for her version of the consciousness code, declaring it "the key" to saving Synths. Hester forcefully grabs Mattie's arm, but is stopped by Mia. Mattie warns Leo his plan will create more tension with humans. "It's time for them to fear us," Mia says. Mattie leaves as Hester runs through the plan to get into the Silo. Mia says she knows a better way.
At home, Karen Voss considers keeping Sam, the Seraph child, but Pete Drummond reminds her that he's "not real." Karen questions if she herself is "real.” Pete receives a call about an article on a cover-up of an unusual Synth malfunction and leaves. Karen tells Sam she is going to go see “a clever lady.” Sam hugs her goodbye, though she knows the gesture is programmed.
At home, Sophie Hawkins carefully tidies the house. Her father, Joe, tries to get her interested in a snack, but she claims to "not require sustenance." Laura apologizes to Sophie for being absent lately and mentions Niska leaving. "They always go away," Sophie laments.
Mattie arrives home and updates her parents on what's going on at the Silo. Laura volunteers to look for Niska and guesses the other Synths will listen to her. Joe hesitates over Laura's involvement and tells her he cares about his own family.
In her room, Mattie reads the letter Odi wrote for her, describing his struggle living a conscious life. Mattie realizes Odi reset himself and cries.
In her office, Dr. Athena Morrow tries to pinpoint Leo's nearby location based on information she got from the Veronica Synth he came into contact with. Karen walks in, unannounced, and confronts Athena about her work on digital consciousness transference. She reveals to Athena her real identity as a synthetic copy of Beatrice Elster.
Dr. Aveling receives information about a malfunctioning Synth. She drives to a warehouse and finds Mia, who pretends to be a scared Synth that’s just gained consciousness. Dr. Aveling recognizes her from when Ed tried to sell her.
Mia is brought back to Qualia UK and Dr. Aveling's co-worker mentions another anomalous Synth being brought in. Dr Aveling thinks there's something different about Mia and wonders if all of the harm they've done to the Synths has been “real.”
Laura meets Pete at a café. She wants his help with keeping "something bad from happening" and insists some Synths can experience emotion as well. Pete lets on that he personally knows it and slips her a piece of paper.
Back at Qualia UK, Karen says she doesn't want to "wear a dead woman's face anymore." She lists all the things her Synth body can't do and wants Athena to transfer her mind.
At the Hawkins home, Renie talks to Sophie about Sophie's Synth impersonation. Sophie says she wants to do away with feelings and looks to Renie as inspiration. Renie, affected, gets up and leaves.
Toby receives a text from Renie that reads, "I don't want to be this anymore." Toby fears the worst and tells Joe.
At home, Renie removes her makeup and contact lenses. She cries as she stares in the mirror.
Toby and Joe rush to Renie's home and find her safe.
Laura finds Astrid in Folkestone, from Pete’s lead. Astrid tries to keep tight-lipped about Niska, but Niska shows her face once Laura mentions trouble with the other Synths. Niska recounts how her own father used her for pleasure, knowing she was conscious, and states that there's no hope for humanity. She grabs Astrid’s hands and says she now has “something worth having.” Niska looks out the window and realizes Laura inadvertently led the police to their location. Niska and Astrid run.
Mattie finds Max and warns him about Hester. Max says his responsibilities are at his new home with Flash and the other Synths that are waking up. Mattie insists Leo isn't "lost" yet. Max decides to leave, and Flash kisses him goodbye.
At the Hawkins home, Renie – now in human clothing – watches television with Sophie and Toby. Laura tells Joe about her encounter with Niska and says, “it’s still not over."
In the Silo, Mia opens her eyes and powers on Hester, who's right beside her. After tying up a security guard and taking his pass, they move quickly around the Silo once they realize they’ve had trackers put in their heads.
Pete arrives home, and Sam tells him Karen went to see a "clever lady." Pete leaves.
At Qualia, Dr. Aveling learns that Mia is fifteen years old and realizes she’s one of David Elster's original Synth prototypes.
Mia and Hester find a room full of conscious Synths and power them on. One of the Synths begs not to feel any more pain. Hester promises to protect them.
From outside, Leo hacks into Qualia's security system on his laptop, while Mia and Hester lead the conscious Synths. They run into Dr. Aveling, who stares in amazement. Mia warns her not to stop them.
In her office, Athena works on Karen’s upload.
Pete arrives at Qualia.
Leo finds the Synths before they exit the Silo. Hester plans to go back and kill those in charge at Qualia to save future Synths. She admits to killing the guard they kept hostage and the woman who shot Ten. Leo is shocked to learn the truth, but Hester declares, "I will not betray our kind." Mia goes after Hester while the Synths follow Leo outside.
Dr. Aveling sets off an alarm, which locks down the entire building and its perimeters. Lights on the fence outside change to red. Athena's office doors lock shut.
Outside, the conscious Synths all drop to the ground once they pass the perimeter. Blue liquid oozes from their eyes and mouths, while Leo unsuccessfully tries to power them back up. Leo, helpless, screams.
Hester finds Dr. Aveling, puts a pen to her throat and demands to know who's in charge at Qualia.
Pete finds Karen locked inside Athena's office. He tells her he's here to take her home.
Hester holds Dr. Aveling hostage and heads to Athena's office. She threatens Athena’s life and demands she come out of her office or Dr. Aveling will be killed. Pete tries to appeal to Hester by sharing his love for Karen, who he says "is like you.” Karen tells Hester she wants to become human and do "what feels right." Hester says she herself should do what feels right and jabs the pen in Dr. Aveling's neck, then into Pete's chest. Mia finds Hester and runs after her. "V" is able to unlock Athena’s office.
Mia runs past a security camera and sees all the fallen Synths outside. She touches the back of her head and realizes that the Qualia tracking device implanted inside her will cause her to expire, too, if she tries to leave the perimeter. She writes code on the computer and disables the lockdown.
Max makes it to the Silo with Mattie. He takes in the scene and comforts Leo. Mia walks outside and addresses a group of five Synths, who survived by not walking past security perimeters. They all head to a truck nearby.
Karen tells Pete she would have gone home to him if Athena had made her human. Karen sheds tears as she holds Pete, and they both express surprise that she can cry. Pete takes his last breath. Athena suggests Karen leave before the police arrive. Karen composes herself and walks off.
Hester walks outside and sees the fallen Synths. In the distance, she spots Leo and the others.