As Clarke tries to talk to the children, a large group of men and women arrive. When they see Clarke's group, they tell the children to get behind them. The adults seem particularly interested in protecting a girl named Rose, calling her a "host." Murphy then starts choking due to the stuff under his skin. Clarke pleads for them to help Murphy, but it's too late. Russell Lightbourne, the apparent leader approaches from the crowd to look at Murphy's condition. He declares Murphy dead but says that death is not the end. He then calls forward a man named Cillian and tells him that Murphy was killed by a toxin from the seaweed. Cillian takes out a snake and lets it bite Murphy. The snake's venom neutralizes the effects of the seaweed, bringing Murphy back to life. Russell explains that the cure was discovered when a man named Gabriel got bitten by a snake and started believing that he's immortal.
Russell orders Clarke's group to be locked up. He starts interrogating them about killing Kaylee's teammates but Clarke says it was in self-defense. Kaylee says that they only stole the ship because they were late and couldn't get to the eclipse shelter in time. Before figuring out what to do with them, Russell tells Raven to bring their transport ship into Sanctum because there are dangerous anomalies outside the radiation shield. He orders Kaylee to go with some of Clarke's people. Bellamy, Echo and Octavia go with Raven to get the ship while Clarke is left behind to discuss her people's future with Russell at dinner.
Clarke asks Russell if they can stay and he invites her to discuss it later over dinner. Abby advises Clarke not to bring up anything she's done back on earth to avoid jeopardizing their chances. Abby also helps Murphy as he regains consciousness. Murphy says that he believes he was in hell when he died. Abby says that people don't go to hell for what they did, but rather why they did it. Murphy admits that everything he's done was always selfish and for himself.
Before the dinner, Clarke and Jordan get acquainted with a girl named Delilah. Delilah tells them that she will officially become a royal after her upcoming naming ceremony in which she would be named Priya the Seventh. She mentions Josephine the Prime, after which she explains to Clarke that Primes are families from the original four families from Eligius III that settled on Sanctum. After that, Jordan and Delilah start hanging out and making out. Delilah asks Jordan to tell her stories, and he starts by telling her everything he was told about Clarke when growing up.
During the dinner, Russell and his wife Simone grill Clarke about her past and loyalties as she tries to convince them to let her people stay. Unfortunately, it turns out that Jordan had already told Delilah about all the people Clarke murdered back on earth; and Delilah had already told Russell about it. Clarke defends herself saying that she did it all to protect her people but they deserve a second chance. Russell is worried that Clarke could turn against them, since they're not her people. So, he denies Clarke's request to stay.
Meanwhile, at the transport ship, Gaia is teaching Madi how to listen to the commanders' voices. Madi says that there's one commander who scares her, and Gaia identifies him as Sheidheda - the dark commander. Diyoza is seated next to them, laughing. Suddenly, people with masks approach from the bushes and shoot them with paralytic darts. The attackers, calling themselves the "Children of Gabriel", start stealing weapons from the ship. Diyoza reveals to Madi that the she's not actually paralyzed because the dart didn't hit her. She asks Madi to blink to indicate how many people are there so that she can make her move and kill them all.
The Children of Gabriel starting cutting off the heads from the bodies of the three dead Primes - Kaylee's teammates killed in the ship. They talk about the need to be ready before "the second moon" for their next activity to impress "the old man." They have some of their people inside the shield to grab the "hosts" before the second moon. With the second moon fast-approaching, Tosh, one of their leaders urges them to but the others want to wait for both their friends. They are also waiting for Bellamy's group in order to capture them and take them to the old man. Tosh urges them to take the victory and leave since they've already got the primes and guns. When they fail to listen to her, she leaves, taking the guns with her.
As Tosh leaves, Bellamy's group arrives to rescue their friends at the transport ship. Bellamy wants to wait until Tosh is gone with the guns before jumping in to save their people. However, Octavia doesn't want to wait. She goes in and within seconds, she kills all the remaining Children of Gabriel at the scene. Diyoza gets up to join Octavia. Bellamy is disappointed in Octavia for killing all those people instead of trying a different option. He kicks Octavia out of the ship and forces her to remain behind alone, claiming that his sister is long dead.
The Children of Gabriel on the inside arrive at the castle. They attack Jordan and Delilah with paralytic darts. They kidnap Delilah and Rose. Upon finding out what happened, Clarke joins forces with Cassius to rescue Delilah and Rose. She manages to get Delilah but gets hurt and starts bleeding. Russell notices that Clarke's blood is black and concludes that she is of royal blood, just like them. Even though all the original Sanctum settlers were nightbloods, only very few inherit the nightblood. The few that do are treated as royals. The Children of Gabriel had targetted Rose and Delilah because they have the royal blood. This makes Clarke a target as well.
Seeing that Clarke has royal blood and helped save Delilah, Russell changes his mind and allows Clarke and her people to stay in Sanctum, as long as they don't bring in more people. They also offer to help Diyoza through her pregnancy. However, when Madi mentions Diyoza's name, they instantly decide to kick her out. They say that Diyoza is known as one of the worst terrorists in history. They force her to leave and stay outside the Inner Sanctum's shield.
After successfully kidnapping Rose, the Children of Gabriel run into Octavia alone in the forests. Before Octavia can attack them, they take advantage of the poisonous trees to paralyze her. They say that they're proud of their work for having taken three Primes, a royal child, a pile of guns and a girl from earth. They hope this will impress "the old man."