Bellamy has been captured by Mount Weather and is chained up and forced through the decontamination process where he is blasted with boiling water, doused with decontamination powder, inspected, given shots, and painfully scrubbed down and is chained up.
Meanwhile, in the Mess Hall of Mount Weather, Maya Vie and Jasper are concerned because both Harper and now Monty have gone missing. Maya tells Jasper he has to make it look like everything is okay and to not do anything stupid. She leaves and Jasper says, "everything is not okay. Time to do something stupid."
In the woods, two Mountain Men are hidden from sight as they watch Clarke riding with Abby and several Grounders on their way from Tondc back to Camp Jaha. One of them has his sniper rifle trained on Clarke just as the group stops. Abby tries to get Clarke to drink some puddle water but Clarke refuses, telling her she needs to get back to the radio to see if Bellamy has contacted them yet. As they're mounting up, Carl Emerson, one of the Mountain Men, tells the other one he has a shot. Just then, the sniper is hit by an arrow and the bullet misses Clarke, hitting a Grounder behind her. Indra and Octavia have found the Mountain Men and Octavia fights Emerson, tearing his radiation suit. Indra tells her to "finish it" just as Clarke rides up and stops her, telling Octavia they want to keep him alive and to check for a patch kit for his suit. Octavia digs through Emerson's bags and finds a picture of Clarke and Lexa on horseback, the intended targets. Indra sends a rider to go warn Lexa of the attempted assassination.
Bellamy wakes up locked in a cage in the Harvest Chamber. He tries to get out when the Grounder in the cage next to him (Echo) tells him in Trigedasleng to be quiet because the Mountain Men take the strongest. Bellamy tells her he can't understand her and she spits on him when she realizes he's a Sky Person. He tells her they're not enemies anymore and he needs to get out of the cage so he can kill everyone in the mountain.
Jasper enters Dante's office and confronts him about Harper and Monty and Dante tells him he doesn't know anything about them being missing. Jasper grabs Dante's decorative sword and holds it to Dante's throat, demanding for him to tell the truth. Dante insists that he doesn't know what happened to Jasper's friends but admits he did lie about Clarke, Maya, and the survivors from The Ark before he turns the tables on Jasper and grabs the sword. He calls in a guard and asks for the whereabouts of Dr. Lorelei Tsing and Cage Wallace. He then takes Jasper with him to find Harper and Monty.
Back at Camp Jaha, Abby is trying to help the Grounder who was shot instead of Clarke. Jackson is helping Clarke with Emerson when Raven says she can hook up scrubbers to the airlock to make it safe to take off Emerson's protective outerwear. The Grounder ends up dying and Indra tells him, Yu gonplei ste odon ("Your fight is over") as she cuts a braid out of his hair. Clarke tells Abby to let her know when Emerson wakes up.
Bellamy is still trying to get out of his cage when Sgt. Lovejoy and another Mountain Man enter the Harvest Chamber looking for their next victim. They start to unlock Echo's cage but Bellamy starts kicking at his cage to get their attention. They pick him instead, shocking him with a stun stick and injecting him with a sedative. He is then strung upside-down and his blood is circulated out.
Maya is in the Medical Ward of Mount Weather looking through patient records as she tries to see any anomalies that might point to Monty's or Harper's whereabouts. Lovejoy enters and asks her if she has seen Thorpe. Maya tells him he just left and as Lovejoy is on his way out the door, a patient's machine beeps, signaling her treatment is done. Lovejoy remarks that the patient finished her treatment an hour early, some kind of record. Maya tells Lovejoy that she thinks she saw Thorpe in the Mess Hall and Lovejoy leaves. Maya then rushes off to the Harvest Chamber where, instead of Monty or Harper, she finds Bellamy hanging upside-down. She injects him with epinephrine to wake him up and asks him if he is from the Ark and if he knows Jasper. Bellamy realizes it is Maya who is helping him and asks for her to get him down. She starts pulling off the electrodes just as Lovejoy walks in and asks what she is doing in there. Maya lies and says she wanted to know what was so special about Bellamy but he is dead. Lovejoy checks the heart monitor without realizing Maya had already detached the wires from Bellamy and starts to get Bellamy down. Once Bellamy's feet are free, Bellamy kicks Lovejoy and Lovejoy pulls a gun on him. Maya stabs Lovejoy in the neck with a scalpel and Bellamy and Lovejoy begin fighting. Maya picks up the gun and tells Lovejoy to stop but Bellamy warns her not to use it because everyone else will hear the gunshot. Lovejoy is gaining the upper hand when Echo reaches out of her cage and grabs hold of his arm to prevent him from stabbing Bellamy with the scalpel that was in his neck. Bellamy then strangles Lovejoy, killing him. He thanks Echo for her help and asks Maya if she is all right. At first, Maya is traumatized but then she resolves herself and tells Bellamy she is fine.
Back at Camp Jaha, Marcus Kane and Abby are standing watch over an unconscious Emerson. They discuss how the Sky People blood heals the Mountain Men. Abby tells him she is worried about Clarke.
In the Harvest Chamber, Bellamy re-enters from the Containment chute wearing Lovejoy's guard uniform. He pushes the button to send Lovejoy's body down into the Reaper tunnels. Bellamy tells Maya she has done enough and should walk away. Maya says, "I'm in," and hands Bellamy Lovejoy's gun and badge. She tells him she can take him to the radio and that Monty and Harper have already gone missing. Bellamy says he wants to see the Delinquents first. Maya explains that everyone knows everyone else as she removes Lovejoy's name-tag and gives Bellamy a hat. As she cuts out Bellamy's tracking device from his arm, she asks him how he knew her name. Bellamy tells her that Clarke told him how Jasper "couldn't stop talking about someone named Maya." She tells him to put the tracking device in his cage. As he does so, he promises Echo that he will be back.
In another chamber in Mount Weather, Dr. Tsing is busy taking more bone marrow from Harper as a caged Monty begs her to stop. Just then, Dante enters and demands them to free Monty and Harper. Jasper helps Monty out of his cage as Dr. Tsing tells Dante that he can't keep them from their birthright: the ground. Dante tells Jasper to go back to the Delinquents and have everyone pack their things because they are going home.
Kane is interrogating Emerson but all Emerson will reply back is with his name and rank. Kane threatens to open the airlock door to get Emerson to talk. Clarke tells Kane that torture does not work. Kane storms off and Abby puts Emerson under 24-hour guard.
Maya leads Bellamy through Mount Weather to an elevator, pointing out cameras and telling him how to get around. As they get on the elevator, another resident gets on with them and chats with Maya. The elevator stops and two more people get on. The elevator stops again and Maya gestures for Bellamy to exit behind the other two people. The man on the elevator notices that there is blood on Bellamy's collar. Maya claims he must have been exposed and steals the man's handkerchief to hold against Bellamy's face as she kicks the other man out of the elevator to "do her job" of tracking down the alleged radiation leak.
Cage Wallace is in the Mount Weather Command Center asking if they have heard from Emerson yet. Dante enters and asks Cage to tell him that Dr. Tsing was working alone. Cage tells Dante they have accomplished great things and that it will get them out of their prison. Dante orders Cage to be taken into custody but the Guards do not respond. Cage apologizes as he tells Dante that the Mountain Men "take their orders from me now" and has Dante arrested instead.
Back at Camp Jaha, Raven and Clarke are listening to the radio when Octavia enters, asking if there is any word from Bellamy and that Lincoln is still missing, too. Clarke tells them that Bellamy will get into Mount Weather. A PA announcement requests Clarke's and Kane's presence at the airlock so Clarke leaves to deal with Emerson. Abby is waiting for Clarke and Kane and tells them that Jackson found genetic anomalies in Emerson's blood that could have only come from a Sky Person. Clarke wants to kill him but Abby tells Clarke she is not in charge.
In Mount Weather, Maya and Bellamy are heading to the dorm when they come across a group of Mount Weather preschoolers. One of them walks up to Bellamy and asks him if he is on a ground unit because his father is training to be an a ground unit. As the boy leaves, his backpack reveals the last name, "Lovejoy." Bellamy finally realizes that the mountain is not just full of Mount Weather Guards but also civilians. Meanwhile, Monty and Jasper are ordering the Delinquents to pack their things because they are no longer safe in Mount Weather. Just as Bellamy and Maya approach the dorm, an alarm is heard and the doors to the dorm close, sealing the Delinquents in. Jasper sees Bellamy and Maya on the other side of the door as Bellamy tells Maya to get him to the radio.
A defeated Clarke comes to tell Raven that Mount Weather has already started bleeding the Delinquents and that it is over. Raven tells Clarke she is not allowed to give up and it is her job to come up with something. Just then, Bellamy's voice rings through on the radio, asking if anyone can hear him. Clarke picks up the radio in relief and Bellamy tells her how the Delinquents have been locked up and that things are going to get ugly. He also tells her they need a plan that doesn't kill everyone because there are kids in there. Clarke tells Bellamy he needs to turn off the Acid Fog and free the imprisoned Grounders. Bellamy asks Clarke to buy him some time so they won't discover him inside the mountain just yet.
Dante is now a prisoner in Clarke's old room in the quarantine ward while Cage is enjoying his new office as the President and all of the Delinquents are trapped in the dorm.
Clarke brings Octavia, Indra, and several other Grounders with her to Emerson's airlock where Clarke makes the guard stand down and tells Emerson to get dressed. They take him outside and bring him to the gates where Kane and Abby try to stop her. Abby tells the Ark Guards to get the prisoner back inside but the Grounders behind Clarke step up threateningly. Clarke tells Abby, "you may be the Chancellor, but I'm in charge," and refuses to back down. Kane tells Abby that it is time they started trusting Clarke. Abby finally gives the order to stand down to the Ark Guards and Clarke makes her way through with Emerson. She tells Emerson to deliver a message to Mount Weather. They have a secret Grounder army that the Acid Fog can't hurt. With the tone generator they got off of Emerson, the Reapers can't hurt them either. Mount Weather has one last chance to let the Delinquents go and the Sky People will let them live. Clarke then releases air from Emerson's oxygen tank and tells him he has to make the eight-hour walk back to Mount Weather in six hours. Octavia asks how this will help Bellamy and Clarke tells her that it will make them look outside for this secret army instead of inside where they might find Bellamy and that Bellamy is the key to everything.