Pike and Kane arrive in Polis with the Grounder army who captured Pike. They find the streets lined with blood and men nailed up on stakes. Ontari arrives and commands the Grounders to take the chip. Jaha and Jackson are also there. Jaha tries to convince Pike to take the chip but Pike refuses. He's led off by his own men from farm station, who have been converted to the City of Light. Jaha also tries to convince Kane to take the chip, with ALIE commenting to Jaha that they need Kane. Kane refuses and throws the chip. He's taken away. Abby tells ALIE and Jaha to leave Kane to her and not to put him with the other prisoners.
In a flashback to the time on the Ark, Jaha, Kane, and Abby secretly meet with Pike. They ask Pike to teach the prisoners a crash course in earth survival skills, revealing that they are sending the delinquents to the ground. They warn him not to tell anyone (including the delinquents) that they are going to the ground or else he'll be floated. He is horrified, wondering what evidence they found of survivability on the ground. Clarke is in solitary, so she will not get the Earth Skills lessons, but Pike is confident that she listened and absorbed those skills the first time. He is less assured of his ability to teach the other kids enough in two weeks. All of the delinquents filter in, as Pike starts teaching immediately.
Bellamy and Clarke drive, attempting to follow Lincoln's map to Luna's village. Jasper is unsure about the likelihood of Luna allowing them to put an AI in her head and notes that they have no way of knowing how far off they are -- the journey could be days. They're unable to continue driving in the rover, so they get out to continue on foot. They hear water and run to find the village, but there is no village remaining where Lincoln once knew it to be. OCatvia screams in frustration and everyone wonders what to do now.
Pike teaches the bored and uninterested delinquents how to start a fire. He asks the delinquents what the key to survival on Earth is. Murphy blows him off and Octavia guesses that the key to surviving is "not dying." Pike yells at them and tells them that the key is to never stop fighting, because the minute they give up, they're dead.
In the present, Pike is thrown in jail. Murphy and Indra are already there. Murphy comments that he told Pike he'd survive. Indra removes a knife from the wall and tells Pike that he'll suffer 300 cuts by her hand, for the 300 of her army that he killed. She begins to cut him. He screams and Murphy turns away, uncomfortable.
Octavia starts a fire by the river. Bellamy tries to help her and she refuses. He wonders how long she'll remain angry at him. Octavia tells Bellamy that every time she looks at him, she sees Lincoln dying. Bellamy counters that he didn't kill Lincoln but Octavia believes he is dead beause of Bellamy. Bellamy storms off, mentioning that Bellamy offered his help and Octavia refused it, that maybe Lincoln would have survived otherwise. Jasper tosses brush into the fire, turning the fire green. Octavia consults Lincoln's diary and realizes that the green fire is the way to signal Luna. She and Jasper go to gather more brush as Clarke gazes after a retreating Bellamy.
Back at Polis, Abby is thrown into the room where Kane is being held. She pretends not to have been converted to one of ALIE's followers in an attempt to get information about Clarke's whereabouts. Abby tells Kane she's afraid and embraces him, as ALIE appears, telling her to try harder to get information from Kane. Abby kisses Kane. Kane shoves her off of him, realizing something is wrong. He realizes she's taken the chip. The guards come in and take Kane away. Abby tells them to put Kane on the cross. They ask him again to tell them where Clarke and the AI are, but he refuses to do that. They nail him up on the cross as he shrieks in pain.
Clarke goes after Bellamy, trying to reassure him that the blood on his hands is not Lincoln's blood and that Octavia will forgive him eventually. She wonders whether he'll forgive himself. He tells Clarke that he was angry at her for leaving but doesn't want to feel that way anymore. Clarke mentions that she is also trying to forgive herself and that they need one another. They embrace. Grounders emerge from the water and take Clarke, Bellamy, Jasper, and Octavia prisoner. The lead Grounder asks Octavia why she signaled. She tells him that they need safe passage and that Lincoln sent them. He hands them four vials of "safe passage" -- it is a concoction that knocks them unconscious. They all take it.
In the past, Pike apologizes to Jaha, having heard Wells was arrested. Jaha explains that Wells will be kept in solitary and will not be attending Pike's classes. Pike realizes that it is because they don't want Wells telling the others that they're going to the ground. Pike begs Jaha to allow him to go to the ground with the kids but Jaha refuses. Pike also wants to tell the kids that they are going to the ground, in order to get them to pay more attention and take the classes seriously. Jaha also refuses, telling Pike to figure out a way to get them to take it seriously.
In class, Pike asks a disruptive Murphy if he'd like to help him with today's lesson. He then punches Murphy in the face repeatedly, trying to goad him into fighting back. The other kids swarm in to help Murphy. Pike tells him that it will take more than just the kids in his station to save him. He chokes Murphy, screaming that it is a life or death situation. Someone hits Pike on the head with a wrench, getting him off of Murphy. Kane and other guards burst in, wondering what's going on. Pike explains that it's graduation and dismisses the shocked kids.
In the present, in the prison in Polis, Indra continues to cut Pike as he talks back at her, saying she won't break him. Murphy convinces Indra to stop cutting Pike because Pike is strong and they will need him alive if they want to fight their way out, past Jaha's army of chipped soldiers. Indra stops killing Pike reluctantly, noting that she will get her revenge on him later.
In the past, the delinquents filter into the dropship which will take them to the ground. Abby puts a tracking bracelet on an unconscious Clarke as she's loaded onto the dropship, wondering aloud what they are doing, sending the kids to the ground. Kane apologizes to Abby. She tells Kane that he's got his extra year.
In the present, Kane hangs from the cross, in excruciating pain. Jaha tells him that his time is up and threatens to shoot Abby in order to get Kane to give himself up and take the chip. Kane finally agrees, taking the chip to save Abby's life.
In the past, the kids drop to earth on the dropship.
In the present, Jasper, Murphy, Bellamy, and Clarke awaken in a hole-filled shack. Luna enters. Clarke explains to her that Lexa is dead and that Luna is the last of her kind -- the last Nightblood. She tells her that Lexa's spirit has chosen Luna as the next Commander and asks whether Luna is willing to accept the flame and become the next Commander. Luna refuses and leaves them. Clarke and the others are distressed and chase Luna out, finding themselves on a tall structure built over the middle of the ocean, where the Boat People live.