On The 100 Season 2 Episode 16, the battle at Mount Weather finds resolution and a new, more ominous threat is revealed in the City of Light.
Tell me, if we released your people and theirs, what would have happened to mine?
If you need forgiveness, I'll give that to you. You're forgiven.
Clarke: I tried. I tried to be the good guys.
Abby: Maybe there are no good guys.
My sister, my responsibility.
Deliverance comes at a cost. I bear it so they don't have to.
Jaha and Murphy are following the drone to the City of Light by boat. Circumstances get dire when one of their crew falls overboard and is killed by a shark-like creature.
Clarke reunites with Bellamy, Octavia, Monty and Jasper in the Reaper tunnels. After their reunion, they split up. Octavia and Jasper take Maya to radiation-free safety on level 5, while Clarke, Bellamy and Jasper attempt to find help by way of Dante.
Indra gives Lincoln a choice. Stay with the Grounders and follow the Commander or leave and stay with the Sky People. He cannot have it both ways.
Abby and Kane are captured and join Raven and Wick, among others, in line for bone marrow withdrawal at Mount Weather. Raven is taken first and puts up a fight.
Dante won't help because he knows that without the Sky People bone marrow the Mountain Men will not survive. His hands are tied, and even when Clarke threatens Cage with his father's death, there can be no resolution. Clarke is forced to kill Dante when Cage doesn't except her deal.
Clarke wants to eradiate level 5, killing all of the Mountain Men who haven't received bone marrow yet. Bellamy is torn because it will also mean killing civilians.
When Octavia is captured, Bellamy changes his mind and agrees to the plan. He tells Clarke they will pull the lever together. Afterwards, Maya is exposed to radiation and dies in Jasper's arms.
Meanwhile, Jaha and Murphy make it to land. Jaha leaves Murphy to follow a drone, and Murphy finds a mysterious house. Upon entering, he finds food and drink and a video of a man's guilt-ridden confession that leads him to kill himself.
Jaha finds the origin of the drones. It is a home occupied by a woman A.L.I.E., who turns out to be a hologram in possession of the disabled nuclear missle Jaha took to Earth.