Spacewalker is the eighth episode of the second season of The 100. It is the twenty-first episode of the series overall.
Clarke returns to Camp Jaha with devastating news. Finn struggles with the aftermath of his actions. Abby gathers information from an unlikely source and prepares for a fight. Meanwhile, flashbacks reveal Finn and Raven's relationship on the Ark.
Clarke arrives at Camp Jaha after speaking with Lexa, the Grounder Commander, who has ordered Finn's death for the massacre of Tondc before their truce with the Sky People can begin. Most of the Sky People want to give Finn up to the Grounders, especially because he wasted three months of oxygen on the Ark for the spacewalk that got him imprisoned. A fight breaks out with Raven punching Major Byrne.
In a flashback to a year ago on the Ark, Finn is helping Raven study for her upcoming Zero-G exam. He asks her what she wants for her birthday and she tells him she just wants to pass her exam. Finn presents her with a handmade metal raven on a chain for good luck.
At Camp Jaha, security has been increased and even Murphy has received a gun. Bellamy and Clarke approach and Finn offers to help with the perimeter security but Bellamy takes him inside. Clarke then blames Murphy for what happened at Tondc, even though Murphy had tried to stop Finn. He tells Clarke to blame herself since Finn was looking for her.
Clarke and Abby visit Lincoln, who is recovering from having been a Reaper. Abby asks Lincoln how to negotiate with Lexa in order to save Finn, but he says there is no way out of it and Finn must die. Octavia asks what would happen to him and Lincoln tells them that because Finn killed eighteen people, he would suffer the pain of eighteen deaths as a result. Lincoln then advises them to do it because one death is better than the elimination of their people. Clarke asks how he could say that about his friend, and Lincoln tells Clarke that some of the dead Finn had massacred were Lincoln's friends, too.
Abby visits Raven where she is locked up in the stockade with Jaha after striking Major Byrne and allows her to go free. Jaha tells Abby she should give Finn up to keep them safe.
Clarke finds Finn gathering supplies to leave. He tells her he is in love with her and that he did everything to keep her safe. He asks her to forgive him and Clarke asks him not to leave. They then hear the Grounders chanting loudly, jus drein jus daun (blood must have blood). Abby walks up to the gate to talk to the two riders Lexa left behind and tells them the Sky People are ready to fight if that is what it comes to. The riders take off back to Lexa's camp and they see someone else approaching: Kane.
Kane, Abby, and a handcuffed Jaha meet to discuss the situation. Kane tells them he has gotten to know the Commander and she might be willing to allow the Sky People to put Finn on trial. Kane tells Abby it is the most merciful outcome for the boy. When Abby leaves the room, Bellamy and Raven confront her, asking her what they're planning to do with Finn and she tells them they are all trying to find a way out of the situation. Bellamy takes that to mean they are giving Finn up.
In a flashback on the Ark, Finn wishes Raven a happy birthday and asks about the scores to her test. Raven tells him she got the first perfect score since they have been giving the test; however, she failed the physical due to a heart murmur.
Back at Camp Jaha, Bellamy finds Finn and tells him they need to leave because the rest of the Sky People are getting restless. They are approached by some Sky People and Bellamy knocks one of them down so Clarke and Finn can escape.
In another flashback on the Ark, Raven meets up with Finn who says he has another birthday present for her. He borrowed a spacesuit from the Maintenance Bay and has found a way to get her the spacewalk she has always dreamed of. Raven talks him through the procedure from his end while she floats freely in space.
At Camp Jaha, Kane and Abby are talking to Lincoln again and ask if Lexa would be willing to accept a deal where the Sky People put Finn on trial instead. Lincoln tells them it is not possible because Finn killed innocent people and they are already lucky because if it were up to Indra, all of the Sky People would be dead. Abby decides she needs to speak with Indra.
Finn and Clarke are headed to the dropship when they are attacked by a Grounder who knocks Clarke out. Finn pulls a gun on the Grounder and begs the Grounder to leave so Finn does not have to shoot him.
Bellamy, Raven, and Murphy (by Raven's invitation) arrive at the dropship and wait for Finn and Clarke.
In a flashback on the Ark, Raven is in the middle of her spacewalk when Finn tells her it's time to come back to the airlock. As Raven is getting undressed, an alarm sounds an "outer door breach."
Finn arrives at the dropship, carrying an unconscious Clarke. Bellamy and Murphy take care of Clarke while Raven tries to comfort Finn.
Abby meets with Indra outside Camp Jaha and tells Indra she does not want to see any more people die. Indra tells Abby that she lies because they saw Finn in the forest. Indra says that only Finn can die for what he has done.
Raven and Finn are watching over Clarke in the dropship and they promise each other that they will always be family. Clarke wakes up and Finn tells her he thought she was dead because of him. Clarke tells him he is not defined by the things he has done. Bellamy shouts a warning to them that the Grounders have arrived and they are surrounded.
In a flashback on the Ark, Raven is trying to figure out where the door breach is. Raven instructs him to use the manual override to get her back into the Ark but in doing so, the breach lost three months of oxygen. Finn instructs Raven to take off the spacesuit and he will wear it instead because Raven is 18 now and she will get floated whereas Finn is still under-age. Reluctantly, she agrees. When people do come, they find Finn wearing the spacesuit, not Raven, therefore earning him his nickname as "spacewalker".
Back at the dropship, Raven wants to give up Murphy instead of Finn because Murphy was also at the village. Finn steps between Raven and Murphy and tells them they need to stay and defend the dropship. He instructs Murphy to go upstairs and watch the back while he takes the lower level of the dropship and Bellamy, Raven, and Clarke will take the front gate. Finn and Raven hug goodbye and Finn tells her, "may we meet again." He then climbs out the bottom of the dropship. Clarke, Raven, and Bellamy are watching the front gate when they see Finn step out in front of them and surrender himself to the Grounders.
In a flashback on the Ark, Sinclair approaches Raven and tells her that he overrode her health rejection and she is now a Zero-G mechanic.
Back at Camp Jaha, Clarke, Raven, Bellamy, and the rest of the Sky People watch as the Grounders start setting up for Finn's execution. Abby says there is nothing to be done. Clarke, Raven, and Bellamy then meet up at Raven's Gate where Raven gives Clarke a knife so Clarke can kill Lexa because Raven owes Finn her life.
Clarke approaches Lexa's tent and Indra stops her with a spear. Clarke presses against the spear, drawing blood. Lexa tells Indra to let Clarke through. Clarke begs Lexa to show how powerful she is by having mercy and that Finn killed those people for her. Lexa tells Clarke that Finn will die for her, then. Clarke asks if she can say goodbye and Lexa allows her to. Clarke walks over to Finn and hugs him, telling him she loves him and that he will be okay. He says, "thanks, Princess" and she steps away from him to reveal that she had killed him with the knife Raven gave her. Lexa tells her warriors that it is done and keeps them from attacking. Raven screams and crumples in hysterical grief while Bellamy catches her and holds onto her.
Lincoln: "They'll take his hands. His tongue, his eyes, and when he grieves will have a turn with the knife. Sunrise the Commander will end it with her sword. But, I've known somebody to survive until the sword. He killed eighteen. He will suffer the pain of eighteen deaths. Then we can have peace."