In Polis, Indra, Pike and Murphy are coming up with a plan to escape. The guards return and Indra is secretly unchained and attacks them, killing them. Most of the grounder prisoners run away and throw A.L.I.E. off of the scent. Murphy says that Jaha's backpack is the way to destroy A.L.I.E. The three of them head off. In the City of Light, A.L.I.E. and Jaha realize they are going for the backpack. They decided to use Emori again to stop them.
On the Oil Rig, the group are listening to Shay reading poetry when Luna enters. She tells Clarke that they leave at nightfall. She then goes to Octavia and Octavia says: So much for the great savior. Luna says that they take in people who are done fighting and avoiding war, Lincoln would never have brought her as all she knows is fighting and death.
In Arkadia, Raven is looking at the code for the city of light and she is amazed at all the minds that A.L.I.E. has taken. She says she has the password but Monty says that they must wait for Clarke. Harper enters and calls Monty away to help her guard. After coming out, Harper reveals that Miller and Bryan have already sealed the airlock. She then kisses him and after telling him she isn't chipped, she leads him away for sex.
Jasper is talking to Shay about her story and she reveals she has never left the oil rig. Clarke says they can't leave but Octavia says they have no choice. Clarke says that they must force the chip into Luna. Octavia says that at least A.L.I.E. gives a choice but Clarke says they have no choice.
In Arkadia, Monty and Harper are lying in bed. She says that this is the first time she has felt safe in a long time. Raven then enters and calls Monty away. She has found a place in the City of Light that she believes contains the kill switch as it is protected heavily. She believes she can stop A.L.I.E. but Monty says they should wait.
On the Oil Rig, Clarke comes to Luna. She says that Lexa was working towards peace and says that Luna can finish what she started but Luna won't take the chip. Clarke then tries to force the chip into Luna but Luna tackles her to the ground. Luna reveals that she didn't leave because she was a coward and afraid of losing, she left as she knew she would win. She killed her own brother in the first round and then was paired with Lexa but fled. She leaves with the flame and says she will get it back when she leaves.
In Polis, Pike, Indra, and Murphy are in the flame keeper's room when guards controlled by A.L.I.E. enter. Pike shoots them down but then Murphy stops him as Emori is amongst them. As Murphy is about to destroy the backpack, Emori tells him it is a nuclear fuel cell and he will irradiate the entire city. Pike says they must destroy it carefully.
On the Oil Rig, Luna won't return the flame but suddenly guards, controlled by A.L.I.E., grab Luna and lock away Clarke, Octavia, and Bellamy. Jasper is saying goodbye to Shay when the guards appear. Jasper sees they are chipped and sends Shay to warn her people not to take the chip but she is shot in the back with an arrow. Jasper is taken. Luna is being tortured by waterboarding. Her presumed lover, Derrick takes the chip to prevent her torture but as he is controlled by A.L.I.E., he takes over in her torture. Clarke reveals that if Luna takes the chip and then the flame, A.L.I.E. will know all and be unstoppable.
In Polis, Pike is working on destroying the cell but Emori is told to stall them. She tells them that if they destroy the cell, everybody in the city of light will die, including her. In Arkadia, Raven has found the kill switch and is planning to destroy A.L.I.E. To stop them, A.L.I.E. sends Hannah to talk to them. However, Monty deletes Hannah with Raven's help and A.L.I.E. manages to disconnect from Arkadia. Monty yells at Raven and says that they should have waited. He angrily gives her the chip asking her if that's what she wants. Murphy stops but Pike takes over and destroys the backpack. Murphy asks if Emori is okay but she just smiles and says they are too late. They cover Emori's face as they leave and when some chipped guards appear, the three of them are gone. A.L.I.E. says it is okay and she is safe. She is revealed to be standing in space, in remnants of the Ark.
On the Oil Rig, Shay frees Clarke, Octavia, and Bellamy before dying. Luna is still being tortured but won't give in. The guards bring in a child to torture claiming that this will force Luna to take the key. Luna fights back and kills the guards. She then begs Derrick to stop but he doesn't and she is forced to kill him too. Octavia frees Jasper and he asks about Shay. Octavia shakes her head sadly. Luna cries over Derrick's death. Later, Luna holds a funeral for the deceased. Everybody drinks to honor their deaths. Clarke apologizes to Luna but says that Luna must take the chip now that she knows what they are fighting. Luna says "You believe that to defeat an enemy who will stop at nothing, you must stop at nothing. How is that different than blood must have blood?". Octavia starts to protest but suddenly collapses, her glass falls to the floor. Clarke realizes they have been drugged and Bellamy and Jasper collapse also. Clarke calls out to Luna as she too collapses. When they awake, they are back on shore and Luna's clan is nowhere to be seen. Bellamy asks what they do now.
Octavia: "So, much for the great Luna. The savior of those in need."
Luna: " You don't want saving. You want someone to fight with you."
Octavia: "You damn right! We're at war. Luna, you can't just ignore that. Lincoln would've wanted you to help us."
Luna: "By becoming Commander? I don't think so. Lincoln knew our rules. We take people in who are done fighting. Done killing. Look at you. Fighting is all you know. Death is all you know. Lincoln would've never brought that here."
Luna (to Clarke): "You believe that to defeat an enemy who will stop at nothing, you must stop at nothing. How is that different than blood must have blood?"
Harper: "I was just thinking, it's been two days with no one trying to kill us."