In a flashback, Dr. Athena Morrow remembers holding hands with her daughter, Virginia, a.k.a. Ginny, near a waterfall.
In the present, Athena arrives at a hospital in San Francisco to visit Ginny, who now lies lifeless in a vegetative state. Athena's ex-husband, Gil, walks in and asks to speak to Athena privately. He reminds Athena that Ginny has been in a coma for three years. "That's not our daughter," he says. He wants Athena to listen to the doctors, "sign the documents" and move on, but Athena abruptly leaves, saying she is going to England and they’ll talk when she gets back.
Laura arrives at the police station for Niska's assessment. Niska is escorted to a chamber where her reactions to stimuli will be measured. "Show them that you can feel," Laura recommends. "Everything depends on that."
At the Synth hideout, Mia tells Max about Ed. Hester overhears. Meanwhile, Max goes to barn and discovers that their prisoner is gone. Max admits to Leo that he freed the imprisoned security agent, but Hester keeps quiet about killing him. Leo insists they all make a run for it to stay safe, believing the security agent to still be at large. Mia plans to stay behind so she can explore her feelings for Ed. Leo advises against it, but accepts her decision.
At the police station, a judge grants 72 hours for Niska's assessment.
Joe shows up for work at the distribution center that fired him, though he's now working in a demoted role in the stock room. He sees his former boss, but doesn’t speak.
During her assessment, Niska is presented with various images on a screen including spiders, laughing babies and a moving roller coaster. She doesn't react.
At school, Toby Hawkins introduces himself to Renie Watson, who doesn't break from her Synth façade. He asks her how long she has been pretending to be a Synth. She says goodbye and walks away. Toby's classmates make fun of him for “crashing and burning with the Synthie.”
Karen Voss returns to work at the police station and tells a co-worker, Tabitha, that everything with her "dad" is going better. Pete Drummond welcomes Karen back and doesn't let on about their relationship. Pete leads a meeting to discuss a recent rise in unusual Synth behavior. After the meeting, Pete and Karen plan to visit a hacker with a connection to a stolen Synth.
Mia finds Ed Hooley at his café. She drops her Anita identity and explains how she was made into a conscious Synth who can feel. Ed doesn’t want to get involved, but Mia confesses her feelings. "I like you more than anything I've ever seen or heard or touched," she says. “Everything normal is bigger and brighter when I’m with you. You make everything more.”
At the assessment, Niska dismisses the validity of the stimuli test designed for humans.
In the women's restroom, Tabitha confronts Karen about her “secret,” but she’s just deduced that she and Pete are dating. She promises not to tell anyone.
At the café, Ed admits he’s lonely. Mia caresses his hand and they kiss.
Neha Patel, the representative for the prosecution, grows impatient with Niska during the assessment. Laura steps in and plays various genres of music for Niska. When a techno song plays, Niska remembers the night she met Astrid at the night club in Germany. Despite that, Niska remains still.
At the Hawkins home, Odi becomes conscious, though he remains tattered with a broken arm. Mattie catches him roaming around the house and stops him before he interrupts Joe's shower. Odi says he can feel.
Pete and Karen arrive at the home of a hacker named Martin and question him about the Synth being sold for $100,000. Martin denies involvement and mentions the word "Seraphim." Pete presses for information, but Martin runs out the back door of his house and jumps the fence, leaving his son behind. Karen finds Martin’s cell phone with only one saved contact listed as Connor. She explains the religious connections to the term "Seraphim," a six-winged celestial being, but Pete remains unsure of how it relates to Synths.
Athena makes an unannounced visit to Professor Edwin Hobb’s home in the U.K. She wants to talk about conscious Synths. Hobb ends the conversation, though he secretly writes a note instructing Athena to meet him outside without her cell phone.
Outside, Athena realizes Hobb is under surveillance. He explains his deal to dodge five years of prison if he leaves his former field alone. Athena offers him $1 million to come onboard at Qualia. Hobb declines. Athena threatens to send him an email, thanking him for "our enlightening conversation on Synthetic consciousness ", thus tipping off the government. She tells him where to find her and leaves.
At home, Sophie refers to Joe by his first name. They cook dinner in the kitchen together. As Sophie grates the cheese, she accidentally cuts herself, but doesn't show emotion over the pain or blood.
At Niska's assessment, Laura presses Niska on why she killed her client, Andrew Graham, at the brothel. Niska explains how Andrew wanted Niska to pretend to be a child and she refused, but he tried to force her anyway. Laura questions if Andrew's fantasies were morally wrong if he thought Niska was just a machine. Niska admits she was scared of being raped. "I'm sorry I can't cry or bleed or wring my hands so you know that," she says.
Ed's friend, Danny, stops by the café and spots Ed and Mia kissing. He walks off.
Hobb agrees to talk to Athena – as long as their conversations are kept general – in exchange for a $1.5 million dollar vineyard.
Leo, Max and Hester remain on the move. Leo still wants to find the Silo to release any Synths being held there, but Max wants to find the Synths currently waking up and protect them. Hester asks if Leo or Max is the leader now.
At the police station, Laura studies earlier camera footage of Niska and notices how Niska touches her wrist where Astrid’s hairband used to be. She searches through Niska's belongings and finds the hairband along with a napkin with Astrid's phone number.
Karen, Pete and the team go out for beers. Off to the side, Pete instructs Karen to act more inebriated. He also reveals his belief that "Seraphim” is a code word for conscious Synths and wonders if there are others like Karen. Karen suddenly appears sick and rushes off. Pete follows and sees that the bag she uses to pretend to digest food has burst. Pete pokes fun at her, but Karen starts to malfunction because of the fluid leaking into her system. Pete brings her to the car and shuts her off so he can drain her.
At home, Joe voices concern over Sophie's odd behavior recently and guesses she's "trying to put up a wall." He wants to get her checked out. Laura feels guilty for not having noticed.
Laura walks into Sophie's room and notices her belongings in meticulous order.
Athena arrives at the Qualia campus in England where she meets Dr. Aveling, the same operative who tracked down Hester after she became conscious. Athena learns more anomalous Synths are held on site in the Silo. She looks out at the compound and smiles.
Later, Athena talks to "V" about the five original conscious Synths created by David Elster and notes that David’s son, Leo, is still alive. "V" tells Athena that she doesn’t just think about waterfalls; rather, she constantly thinks about a specific waterfall. As "V" describes the waterfall, Athena looks at a photo of Ginny and herself posing in front of the same waterfall.