Due to inexperience with the motorcycle and dizziness, Clarke
ends up crashing destroying the radio in the process. With the Sanctum
guards on their tail, they need to find a place to hide. Josie
says she’ll help (only when Clarke tells her she’ll take the Mind Drive
out herself and die), so she shows Clarke a hatch where she used to do research studies. They’re safe from the guards, but Clarke starts to have a seizure. Josie tells her to fight through it, otherwise, they’ll get stuck in this hatch until the body dies.
Raven and Abby get arrested immediately upon returning to Sanctum with Simone. Russell catches his wife up on everything that’s happened: Clarke is still alive and missing with their daughter’s Mind Drive, and he’s holding Clarke’s people captive as insurance. He informs her that Madi killed Miranda; due to Madi being a nightblood she will be spared, and someone in her place will be killed.
Ryker is doing his best to start a peaceful revolution. He reveals to Delilah’s parents and a man named Ty that everything they believed was a lie. Ty was forced to put his baby in the Offering Grove a few years ago, which led to his wife putting herself in the Offering Grove, so he takes the news particularly hard.
Gaia and Echo watch from above, where they’re hiding from Russell. After the carriers leave, Ryker tells them that a person from their group is going to be executed. Echo has a better plan: Ryker can put a scope on her bow and she can execute Russell instead. Ryker doesn't like this, but he goes along with it since they know his secret about letting Gabriel escape.
In the Sanctum jailhouse, the group has to decide who will be executed. Of course, the logical choice for everyone is Murphy. Since she recently learned that her daughter’s brain is playing host to two people, Abby is not pleased to hear what Murphy did to help the Primes. She slaps him across the face and says if Echo doesn’t find a way to save them, he’s going up as tribute.
Ty, the man Ryker revealed the truth to, has asked for a meeting with the Primes. He claims to know where Echo is hiding, but really he wants to take this opportunity to murder Simone. He smashes a glass goblet on the table and stabs her in the throat with a shard. “Death to primes,” he shouts as the guards drag him out. Russell grabs his wife, but realizing her injury is fatal, he promises to bring her back.
Over in Clarke’s mind, the two women are not doing well. Josie’s memory books are all over Clarke’s side. The only way to get the alarms to stop is to throw Josie’s books out the airlock. Josie is having a hard time letting go of these memories, like the time that Gabriel woke up in his second body. One she’s probably happy to get rid of, though, is when her father murdered her with an ax during the first red sun. When she drops the book, an ax falls to the ground.
The more books they throw out, the worse it gets. Clarke’s Eligius hallways are littered with books and memories, more and more by the minute. Clarke says they have to get rid of it all. She sets the airlock to open with the inside door still ajar. She tells Josie to take cover in her room, and then her nemesis disappears along with all the books. When Clarke opens up her door, the hallway is clear and Josie’s door is back. However outside of the mindspace Clarke's physical body is being choked to death by tree vines.
Gabriel and Octavia find Clarke, only it’s not Clarke. Josie is back in control of the body. They get her out of the bunker and tell her to keep quiet because the Sanctum guards are all around. Instead, Josie starts yelling and the guards surround them. Josie tells her bodyguard Jade, “Kill the girl, take Gabriel prisoner, and get me home.”
Before they can do any of that, one of the bodyguards shoots all the others, except Jade. He takes off his helmet… it’s Bellamy. Octavia runs and hugs him and he doesn’t quite reciprocate. He sends Jade to go tell Russell that Josie is alive and if any of his people get hurt, he’ll never see his daughter again.
Back at Sanctum, Gaia “gets caught” and ends up in jail with the others so she can clue them all in to Echo’s plan. Madi is not pleased with her banished flamekeeper being there, though. Abby suggests they just take the flame out of her head, but Gaia says she changed the passphrase, so they can’t. Emori explains to everyone that Sheidheda was dealt with in his time by his own flamekeeper murdering him. It was his fourth flamekeeper because he had murdered the other three. Abby says they can’t kill Madi, but Gaia points out that if they survive this and she’s able to get her army back from Eligius, she’d be worse than Blodreina.
Raven has another idea. She says if Sheidheda was able to quiet the other commanders, he must be separating them isolating them in the code somehow. As a result, they could delete Sheidheda from the Flame and get rid of him for good though Becca's notebook is in Ryker's shop. However the guards come into the cell with new orders from Russell: except for Madi, they all will die.
With his people gathered round, Russell has everyone, plus Ty, tied to stakes. He walks around saying how there will be no forgiveness. Echo is knocked out by Ryder who thinks killing Russell right then and there wouldn't change anything however Murphy has a idea Abby could make nightbloods with bone marrow. Russell says they tried it before and it didn’t work, but Abby says she knows the right formula and if any of them die, they’ll never know what it is.
Russell pardons Abby and her people so she can get to work right away. She says she’ll need a nightblood donor and suggests Russell himself. He says Madi will do. Abby starts to protest, but Raven says she’ll work fine they’ll just need a computer. Raven tells Gaia to get Becca’s notebook and they can save Madi from Sheidheda. However Ty is killed is for assassinating Simone.
Over at Gabriel’s encampment, he has Clarke/Josie hooked up to scanners. He can see two brain wavelengths. Josie is still awake and tells him that Clarke was able to stay in her brain thanks to the neural mesh in her head. Gabriel explains to Octavia and Bellamy that he’ll stop Clarke’s heart, take out the Mind Drive, and restart Clarke’s heart. But when Bellamy mentions using Josie’s mind drive to broker peace, Gabriel gets hesitant. He knows that means she’ll resurrect again, and that someone else will die because of it.
Josie pleads with Gabriel to let her keep this body, so “no one else has to die,” saying that the two of them can live out their days in their current forms. “I have loved you for centuries,” he tells her. “We had our time I have to let you go now.” And then he injects her with a serum to stop her heart.
Clarke wakes up back in the Ark, and Josie’s door is missing, but Josie isn’t. She is still holding the axe from her father’s memory, and she slices Clarke’s throat with it. Josie used the mesh in Clarke’s mind to stick around even though the Mind Drive was out. Josie claims that Sanctum is hers and that if Clarke is allowed to live, she will kill everyone there.
In the real world, Octavia, Bellamy, and Gabriel see that the two wavelengths are there, but are helpless to do anything, as Gabriel believes that Clarke's brain can no longer handle the strain. However, Bellamy is determined bring Clarke back and performs CPR, urging Clarke to fight. Hearing him, Clarke grabs the axe and swings it through Josie, destroying her. Clarke wakes up and reunites with Bellamy with Gabriel and Octavia looking on. On Gabriel's EEG, Josie's brain wave pattern flat-lines as she is destroyed for good.