Inside the palace, Madi
is strapped to an operating table and getting her bone marrow extracted. She may be weak physically, but she is seething with rage and Sheidheda
inside her. He wants her to kill everyone who gets in their way in order to get revenge for Clarke, but Madi only wants to kill Primes
. However that still doesn't stop her from lashing out at Dr. Jackson
, who Sheidheda
wants dead regardless.
In Gabriel's tent after Clarke wakes up, she assuages Bellamy's fears that he did the wrong thing in saving her. She thinks his plan was good, but there's the small problem that Josephine's mind drive is now a blank slate. Gabriel thinks they should put the mind drive back into Clarke and let Russell think it's his daughter. Bellamy thinks this is too dangerous, even though the mind drive doesn't have Josie in it.
Still in Sanctum prison, Miller and Gaia are trying to escape. Murphy is standing around offering no help when Jade comes in and says that he’s wanted in the palace. He’s taken in where Russell is torturing Echo to learn who else knows “the truth” aside from Tai. She doesn't give up anything, so Russell tells Ryker to take her to the machine shop and test Abby's bone marrow on her. As she's being dragged out, Murphy tells her in Trigedasleng that they're sneaking out to the machine shop to get Becca's book, and she needs to stay alive until then. And because Echo spits back venom at Murphy, Russell believes he's still on the Primes' side. He wants him to go with Jade and bring back Josie. If he doesn't succeed, Russell will kill Emori.
Clarke suggests that since Gabriel built the shields and is a Nightblood, he could walk through the radiation barrier at any point and lower the shields, but Gabriel doesn't want to since he believes the innocents inside the city are savable. The only reason he fled in the first place is because he was going to be burned at the stake until Ryker saved him. When asked what his crime was, Gabriel tells them it was destroying a stash of genetically engineered embryos that Primes had kept to be used for their future Nightblood hosts.
After continued aggression from Bellamy, Octavia finally asks to talk to him outside the tent. When she exits, Gabriel explains that Octavia has changed. She went through the anomaly, “the greatest mystery of Sanctum,” and came back out. Bellamy ponders Gabriel's words, but doesn't get the chance to act upon them as the tent is surrounded by the remaining members of the Children of Gabriel.
Gabriel exits the tent and tells his followers the truth after a decade, “The old man is dead, so is Xavier.” At first they're in disbelief as he tells them that his anger over his resurrection led him to kill Eduardo, which was pinned on a Sanctum guard. Xavier's sister Layla takes this the hardest and is ready to kill him as 'revenge', but Bellamy says she needs to keep him alive to deliver the bomb.
He says that Gabriel can make a bomb with the red sun toxin, walk through the radiation shield, and release it on Sanctum. Then they can find Raven, have her take down the shields, and use the chaos of evacuation to kill the Primes and rescue his people. However Layla still believes Clarke is Josie and orders Gabriel to kill her. After he shows her that Josie's mind drive is out of Clarke's head, Layla and the men agree not to harm her for now. Bellamy and Octavia go on a toxin hunting mission.
In the machine shop, Echo asks Ryker to stop and get back on the right side of this fight. However he refuses believing Echo's promise will not save his mother or him and leaves.
Back at the tent, Gabriel tells Clarke one of the reasons he was disillusioned with the Primes is that they were making a bomb just like this. They found that the aggression from the bomb made the people faithful to the Primes go after those who weren’t, thereby cementing their godlike status. That’s when Clarke realizes she’s facing Mount Weather all over again. She doesn’t want people to die, and she has a new plan: Use just enough of the toxin to make the insects freak out so the people will flee, but no one actually ingests it. Without the craze of the toxin though, they’ll have less time and will need the shield to be down beforehand; she will have to imitate Josie for this plan to work.
Bellamy hunts for mushrooms covered in the toxin while Octavia tries to explain herself and her time in the anomaly. She says she knows why the thing spit her out: “It was for you.” She explains that she knows he was right to leave her behind, and she sees the damage she did — but part of the reason she was so lost was that he wasn't by her side. “Without you as my compass, I was lost,” she explains. “I couldn’t find my way out of the dark.” Bellamy takes this in and says he knows she's his sister, “but you’re not my responsibility, not anymore."
Ryker grants Echo her last request to tell him something from her past that she hasn't even told Bellamy. In a flashback, we learn that Echo's birth name is Ash and she had an friend named Echo until they were forced to fight each other to the death to prove worth to Queen Nia. Through tears, the real Echo tells her friend to fight back so maybe Queen Nia will see value in her, too, and stop this. Echo is able to tackle her friend, but she can't take her out before Ash pushes an arrow through her stomach and kills her. The queen says Sangedakru is expecting a girl named Echo, so Ash becomes Echo.
In the present day Echo says she was already wiped as an person when she took on her friend's identity; however, even though he's sympathetic, Ryker can't let her go. Gaia and Miller, who escaped from Sanctum jail, burst in in search of Becca's notebook. The two release Echo who kills Ryker, telling him "hesitation is death," quoting Queen Nia's words to her.
Back at Gabriel's tent, Bellamy is learning the plan to use Clarke pretending to be Josie and he's not pleased. He wants to do it the way that probably kills lots of people and doesn't put Clarke in danger. “What would Monty do?” Clarke says. He still doesn't like this plan, but Octavia says, "If we can spare innocent lives, we should."
Outside, there's a commotion. Murphy and Jade are there to collect Josephine as the guards battle the Children of Gabriel. After collecting “Josie”, Jade wants to shoot Layla, but Clarke says, "This one is mine." Jade exits the tent and Clarke shoots the ground. Before untying Bellamy, Clarke escapes with her Sanctum guard. Bellamy agrees to go along with Clarke's plan for Monty's sake. Layla is clearly very confused, but gets that Clarke isn't Josephine after witnessing Clarke save her life and Clarke's interaction with Bellamy.
Clarke is brought before Russell and succeeds in tricking him into believing that she is Josephine, claiming that she has no Mind Drive as she hung on through the neural mesh and killed Clarke in the Mindspace. Clarke questions where Simone is, and Russell shows Clarke her Mind Drive and mentions his plan to bring her back through Echo. However, Josephine's supposed return causes Russell to put this plan off to bring Clarke to Madi instead. Clarke sees Madi and acts like Josie in front of her causing Madi to go berserk, leading Clarke to sedate her. Still keeping her cover though secretly disturbed, Clarke asks Russell "how many doses can we get out of her before she dies?"