The fourth season picks up right where we left off. Clarke has just learned the human race is doomed to face an unbeatable enemy. Alie was telling the truth. The remaining nuclear reactors on Earth are melting and will set the atmosphere on fire. Can our heroes find hope knowing the end is inevitable? Will they spend their remaining days trying to survive? Or will they use their limited time to finally live? The stakes have never been higher, alliances are breaking, and the world is about to collapse. Civility has no place at the end of the world and there's no telling what lengths our heroes can and will go to in order to survive.

Clarke and her friends struggle with how to proceed after the fate of the world is revealed.

The burden of leading weights heavily upon Clarke and Bellamy when different challenges force them to determine who will live and die.

Jaha leads Clarke and Bellamy down a road to possible salvation while tension rise in Arcadia and Polis.

Continued struggles with leadership and trust in Arkadia and Polis take violent turns while Abby leads a team to a distant location hoping to find answers.

Clarke makes a desperate plea with a former allied force in an attempt to avoid a war and ensure the survival of her people.

Clarke and Roan must work together in hostile territory in order to deliver an invaluable asset to Abby and her team.

Clarke's arrival on the island quickly takes a turn for the worse. Meanwhile, Bellamy tries to avoid further tragedy in Arkadia.

After a disappointing discovery, Clarke and Abby question how far they're willing to go. Meanwhile, Jaha finds a lead to the mysterious Second Dawn.

Jasper and Bellamy go on a quest. Meanwhile, Clarke struggles to keep the peace after word of Jaha's discovery spreads.

Octavia fights in the final battle for her people's survival, but not everyone is willing to play fair.

Clarke faces the consequences of her fateful choice.

Jaha and Kane disagree over how to handle their grim reality. Meanwhile, Clarke leads a group to save a friend.

It's a race against the end of the world as Praimfaya arrives forcing our heroes to make impossible decisions to ensure their survival.