Starting where the cliffhanger of the previous episode left off at. The Lightbourne family is trying to take Eligius IV by force. Indra realizes pretty quickly that this isn’t really Clarke and Abby, and she’s not ready to back down. But when Gaia slightly shakes her head, she lets them onboard.
Russell and Simone throw all of them in the mess hall and explains that the plan is to plot a course for Planet Beta, which is a 20-year journey. Wonkru can either go with them in cryo peacefully or die right now. Madi, possessed by Sheidheda, only has to say one word (“gonplei") and her men fight for her, but Russell and Simone take them out before they can do much damage. Simone is ready to put a bullet in Madi when Clarke steps in front of her. She tells Madi that no one gives orders except them and then knocks her out. Before leaving the room, Clarke whispers to Gaia that they must save Madi and she’ll handle the rest. Armed with Becca’s book, Raven can get to work.
Outside the mess hall, Russell is terrified by how loyal Madi’s people are. But Caleb Prime says he’s more worried about Planet Beta not being survivable. Miranda agrees. Russell says all they have to do is access the mind drives from the “other teams” to find out, and if it’s not, they’ll go on to Gamma, then Delta, then Epsilon. Jasmine just watches. After settling that, Simone brings it back around to Madi: “That child is a problem,” she says. Clarke says it’s important to keep her since she’s a host claiming that Madi will be her host after Clarke's body eventually dies one day, so they decide instead to wipe the minds of her entire army in cryo.
On the ground, Bellamy and his crew are trying to determine how to get out of their cage when someone gasses them. They wake up bound and gagged in the tavern. A woman dressed in religious clothing tells Xavier’s sister, Layla, “Your blood or the blood of Sanctum.” When Layla refuses Sanctum’s blood, she slices her throat with a knife. She goes to Miller next and he begrudgingly accepts a sip of the blood cup. She’s about to offer the cup to Octavia when Daniel Lee (Murphy) and Kaylee Lee (Emori) come in.
The Prime Priestess, Tory, says she’s purifying Sanctum. Emori says that protocol adjustments are just for “our people,” so they’re taking all the Earth people back to the palace. As they’re walking out, a man named Zev says he missed Daniel and gives Murphy a great big kiss. There isn’t time for Murphy to process that though because he’s got to get his friends to safety and that proves to be difficult when the still toxin-ed up religious zealots in the street trying to kill the Earth people for taking their Russell Prime away. Luckily, Gabriel is at the gates of the palace to get them all inside in time.
Back on Eligius IV, Simone is ready to mind wipe all of the people in crypods. Clarke stalls by saying Simone does not look well, that maybe she is having to fight Abby mentally since she had neural mesh in her head, too. Russell says he checked before wiping her, and she’s definitely Simone. They tell her to hand over the serum, and when Clarke pulls away, Simone and Russell realize this isn’t their daughter. She pulls a gun on them and Russell begins to cry. “Believe it or not, I am sorry for your loss,” Clarke tells them and runs away.
Russell is an emotional mess, but Simone is all business. She says they have to find Madi and use her as leverage. Raven is hard at work trying to save Madi; she’s finally gotten past the AI security, but it looks like Sheidheda has created a kill code. Either they let him live in Madi, or they have to destroy the flame. When Madi starts waking, Gaia tells Raven to kill the flame a bold move for the last remaining flamekeeper. The program starts executing, but Russell stops it when he comes in with his guards and unplugs Madi.
Simone is doing her part of the plan tracking the Mind Drive in Clarke's head to find her on the ship along with Caleb, Miranda and Jasmine, but Clarke had anticipated this. She’s strapped herself in next to the airlock doors. She tells them to put down their weapons or she’ll float them all. Just then Simone turns her gun on her people. Jasmine, Miranda and Caleb are shocked and lay their weapons and trackers down. Simone tells Clarke she’s been pretending to be Simone and that it’s still Abby in there. As much as Clarke wants it to be true, she isn’t fooled, so she asks what her father’s name is. When Simone hesitates and starts to turn her gun again, Clarke pulls the airlock switch. They all float out, but Simone grabs hold of Clarke. With tears running down her face, Clarke has to push her mother’s body out into space shutting the door behind her.
From the command deck, Russell sees his family floating and he’s ready for blood. He goes for Madi, but Sheidheda is in full control. He says Russell could shoot Madi, but that would just provide Clarke momentary sadness; Sheidheda can offer sweeter revenge. Next thing you know, Russell is walking into the mess hall with Madi and her entire army at his side. Refusing to believe Madi is lost for good, Clarke puts a gun to her own head. She tells Madi that she loves her and begs her to come back. She says she’ll pull the trigger in 3… 2… making Madi wake up. “Take the Prime and his men,” the commander orders.
Madi has just enough time to make it to Clarke before Sheidheda fights her for control again. He’s strangling her in the Flame causing Madi to have seizure in real life. They rush her back to the med bay so Raven can attempt to pull the kill switch. This time it works the code is wiped. However Madi isn’t waking up. Raven realizes it’s because she still has the flame in her head. Clarke tries to cut it out, but the scalpel is shaking in her hand. Jackson takes over, and once the flame is out of Madi, she wakes up.
The bad news comes right after. Niylah notices the computer says, “Upload complete,” meaning Sheidheda uploaded his consciousness to an unknown location.
Back at the palace, the gang tries to rally Jordan. They get to him in time, but he’s still in a trance. Bellamy doesn’t understand why these people are still fighting like this when they know the truth. Octavia explains that if they accept the truth it means their lives were for nothing. “It’s why I burnt the farm,” she reveals, but Gabriel thinks they can use this blind faith to their advantage he just needs Murphy to help him.
The plan is simple go back to the tavern and get the Children of Gabriel out, but Murphy says this isn’t their fight anymore; He got his own people out, so he’s done. Octavia says she can’t let them die, so she signs up to go fight. “Side by side,” Bellamy says as he volunteers to go, too, and Echo adds, “I guess it’s time to do better.” Emori is ready to go as well, but Gabriel says Kaylee was always against the Adjustment Protocol, so she’ll need to stay with Jordan. Never one to be left out, Murphy decides to go. “If I die, you’re bringing me back,” he says to Gabriel, who says not a chance.
Murphy and Gabriel approach the tavern together. He tells the priestess, Tory that they both need adjustments. Murphy, pretending to be Daniel Lee, tells Zev that something went wrong in his resurrection, which is why he doesn't remember him. As they prep Murphy and Gabriel for their brainwashing, Tory walks out and boards up the door. Then she says, “We purify Sanctum through fire,” and starts dousing the place with gasoline. Bellamy, Echo, and Octavia take matters into their own hands and fight everyone who tries to light a torch to the tavern. As the conflict intensifies and the four gain the upper hand, Tory, in a last ditch effort to "purify" Sanctum", douses herself in gasoline and lights herself on fire, rushing towards the tavern. Octavia notices and tackles her, knocking her down and knocking her unconscious. As Tory dies, her attack a failure, Octavia quickly removes her jacket, which is on fire and covers Tory's corpse.
As they assess the damage, Gabriel notices a tattoo on Octavia’s back. It’s a replica of the anomaly stone, which he’s been studying for 150 years. He’s not sure what it means, but she is. “It means I have to go back,” Octavia says.
After everyone from space comes down to Sanctum and reunites, Gabriel, Octavia, Bellamy, and Echo set off for Gabriel’s tent. He shows them that it was built on a hatch. Inside the hatch is a spiral sculpture floating in the air. It’s covered in symbols that match the ones on Octavia’s back, with the only difference being some of the symbols on her back are in red. Echo suggests this to be some kind of code. Gabriel agrees, testing this theory by touching the corresponding letters on the stone. He leaves the final symbol, an “O,” for Octavia to press. When she does, nothing happens for a moment. All of them are confused and slightly concerned, until the anomaly flare encompasses the entire area.
They go back above ground, all of them witnessing the anomaly before them, but Octavia sees something more. "She's here," Octavia says. The silhouette of a woman appears, walking through the anomaly towards the tent. "Diyoza?" Octavia asks. The woman enters the tent, instead being Hope Diyoza, as a grown woman with anomaly symbols tattooed onto her face. "Hope!" Octavia exclaims, approaching her quickly. Hope explains she couldn’t get out of it, and “he has my mother”, before hugging Octavia and apologizing. Octavia answers, “Be brave and tell him it’s done,” right before it becomes visible that Hope stabbed Octavia in the stomach. Octavia loses consciousness fast and collapses while Bellamy catching her in shock. As Hope then passes out into Gabriel's arms, Octavia's body vanishes instantly, as does the anomaly. A horrified Bellamy repeatedly screams Octavia's name, running out of the tent and dropping to his knees in terror and confusion.