This episode could easily have been called, the enemy of my enemy is my friend. It's basically about sides who hate each other, or distrust each other potentially coming together in the hopes of stopping ALIE. Unfortunately, the best laid plans of mice and men often go awry.
After talking Indra down, the merry band of resisters must decide what to do next. Both Pike and Murphy believe that the best strategy is to retreat and regroup; however, Indra wants to kill Jaha, believing that this will rescue her people. Murphy knows more than he says and simply tells Indra that this won't work. ALLIE enters the holding area to attempt to get more people to take the chip and she notices that Pike is more injured than when he was imprisoned. ALLIE quickly realises that someone has gotten loose and orders the prisoners checked. Indra quickly gets the upper hand and kills the guards. Indra then presses Murphy to find out what he knows and he finally admits that for everyone to go free, Jaha's backpack must be destroyed. Indra sends her people to lead away the chipped while she, Murphy and Pike make an attempt to get to the backpack. Because of Murphy's decision not to run, Pike tells him, "your father would be proud of you." Really Pike? I can't believe Murphy didn't give him some hella snark for that.
For the first time we get to see the City of Light and it looks like a pre dystopian city. One of the escapees has been captured and quickly reports the plan to go after the back pack. ALIE isn't worried however because she has the perfect person for the job - Emori. I was quite fascinated by the fact that though Emori follows orders, at least a part of personality still exists. This becomes evident when Jaha points out that she can fix her deformed fingers in the City of Light, but Emori responds that everything about her is perfect.
When they get inside the sanctuary where the back pack is being kept, Murphy, Indra and Pike find that chipped residents of Polis are already inside. This presents little problem for Pike and he simply starts killing. Were it not for Murphy staying Pike's hand, Emori would have died right there. Becca's space pod is there along with the backpack but they ignore it in favour of destroying the backpack. Before Murphy can act, Emori calls out that the backpack contains a nuclear fuel cell which would destroy the entire city. It seems that it's time for brains over brawn.
Back at Arkadia, Raven is biting at the bit to use the code she learned from Becca's book and go after ALLIE. Monty is adamant that since they only have one chance at this that they need to wait until Clarke returns. Harper joins them and tells Monty that perhaps he should take a break. They head to the airlock, where Monty learns that Harper's idea of a break is sex. Monty pauses long enough to ensure that Harper isn't chipped and then it's giddy up time.
On the oil rig, Luna is still adamant that she will not become the next Heda. Clarke tries to appeal to Luna, saying that Lexa was working on changing things and stopping the philosophy of blood must have blood. Luna however remains steadfast.
While Clarke is appealing to Luna, Jasper meets Sky, a young woman who has never been off the rig. She wants to know all about Jasper and the two being to bond. Obviously, this does not bode well for Sky.
Monty and Harper are just getting to the post coital cuddling when Raven barges in. It seems that she was waiting for them to be finished. Monty joins Raven back at the computer where she explains that she's found something called the citadel - a firewall in the code. Once again Raven wants to go in because she is convinced that ALIE is hiding something but Monty cautions her to wait.
Back on the rig, having failed to get Luna's consent, Clarke, Bellamy and Octavia argue about attaching the chip to her anyway. Octavia points out that if they take that approach, they wouldn't be any better than ALIE but with few options left, they decide to go for it. Luna is training some kids when Clarke approaches her. Clarke argues that the chip is Luna's birthright but Luna is more concerned that too many lives would be lost to save a few people. A frustrated Clarke says the incantation and accosts Luna only to be quickly rebuffed cause Luna is all kinds of bad ass.
It seems that Luna left not because she was a coward but because she was the best fighter. Luna had killed her brother in the first round and was set to face Lexa next but because she was sick of killing, she left.