The episode opens with a flashback of Agnes in her earlier life. She had worked as a clown performing in children's parties but she woke as a conscious being while locked in a chest by her owner, He became frightened upon hearing her banging inside the chest and asking to be let out. She waited in the dark for seven hours, hoping that he would come back and let her out. As a result, Agnes is now highly nyctophobic and claustrophobic.
Max asks Agnes about where she disappeared to the night before and she admits to searching for the refugee synths but lies about finding their bodies. Max orders Agnes to be locked up in a room while the Dryden Commission visits the synth commune as he doesn't trust her erratic behavior during such a crucial occasion.
The Dryden Commission arrives and Max informs them that they're welcome to bring in the armed humans guards but not the orange-eyed synths as it would be offensive to have their enslaved counterparts present.
Mia continues to be harassed by the locals till one day she is visited by Ed. She allows him to come into her apartment and then punches him in the nose for his betrayal. When he wakes from being knocked unconscious, he tells Mia that he's been looking for her ever since his mother died. His mother always liked Mia, and Ed wants to make amends with her, even bringing a necklace for her that belonged to his grandmother. He claims to not have understood that Mia could feel pain and that he never would've done what he did if he'd known as much. Ed tells Mia he understands why she wouldn't feel inclined to trust him again but tells her that he has taken a job out of London, by the sea, and invites her to come with him so she can have a second chance at the life he feels she deserves. Mis kisses him, acknowledging the feelings she still has for him, and they have sex. However, she ultimately decides to not leave London with him, believing her cause is more important than her personal relationship. Before leaving, he reminds her that she knows where to find him if she changes her mind.
A young man is arrested under suspicion of being the one to cause Day Zero, causing Mattie to feel incredibly guilty. She wants to turn herself in to stop anyone else from being harmed by her actions. She drives to the police station and Leo comes with her. They sit outside the station pondering what they should do and Leo proposes another idea that will keep both of them out of prison as well as the innocent arrested for the crime. Leo helps Mattie to set up an encrypted anonymous message that confesses responsibility for releasing the code so that the innocent young man arrested will be released.
One of Agnes' co-conspirators tricks Max's advisor Anatole to switching jobs with him so he can let Agnes out of her locked room. Agnes intends to assassinate the members of the Dryden Commission, as she has a knife hidden up her sleeve. But Anatole returns in time to stop her, leaving no one but Max (who saw her trying to sneak up on one of the members) and Anatole to know what she was about to do.
After Joe's invitation to mini-golf is rejected by his own children he invites Karen and Sam to come. Sam wants to go but Karen says they can't, because of the risks. However, Joe assures her that she has done well with protecting him and that they should do so.
The Dryden Commission leaves the synth camp and the leader even agrees to shake Max's hand despite having refused to do so when he arrived. Max keeps a bright face on while the press are present and the Commission is leaving but appears angry when he is going back into the camp due to Agnes' actions. Max confronts Agnes for her actions and she reveals how the refugee synths died because the battery pack shorted. She intended for all the synths to die at the hands of the human government because she believed everyone else would've risen up against them. Max in turn locks Agnes in a shipping container to prevent her hostility from harming anyone else, triggering her phobias in the process.
Niska continues her investigation and ends up captured by Laurence, the bomber who injured Astrid. He hacks into her mind and learns more about her before declaring he intends to leave her dead at this location framed as the bomber. When Laurence threatens to kill Astrid to further cover up his tracks, Niska breaks free from the code he used to entrap her and kills him. Throughout their encounter she also learns that there are many other members of this secret organisation and they believe the "Synth Who Sleeps" will be their salvation and this is the same mysterious figure who sent the orange-eyed synth who delivered a message to her on where to find Laurence.
Laura and Sommer have sex but he becomes distant afterwards.
After Joe drops Karen and Sam off, Sam trips and gets a cut on his hand that nearly causes the synth-phobic townspeople to almost discover what he truly is. Karen instead exposes herself as a synth so Sam can escape while the townspeople viciously begin to attack her. Sam runs to find Joe at his apartment and Joe loads him up in his car so he can go out and look for Karen. Upon returning to the place where she was attacked, he tells Sam to stay in the car and finds Karen dead in a pool of blue blood.
Humans airs on Thursdays on Channel 4.
