Plot summary
In Polis, Kane and Bellamy are sentenced to die when Roan ends the alliance with both Skaikru and Trikru. Abby, Raven, Murphy and Luna return to A.L.I.E.'s island to discover how they can use Luna's Nightblood to save the human race from the radiation. Drones fire on them, resulting in Nyko's death and driving Luna to her breaking point. Echo hunts down Octavia and after a sword fight, Octavia is stabbed and falls off a cliff, but survives. Also, Monty and Jasper discover and expose Clarke's list of 100 names forcing Jaha to resolve the conflict.
Credits
Adapted from Wikipedia contributors, List of The 100 episodes. HTML formatting and reference markers removed.