The 100

About the series

Contains story spoilers.

After nuclear catastrophe, the Ark’s failing life support leads its authorities to send one hundred juvenile detainees to Earth to test whether the surface can sustain people. Clarke Griffin, a doctor’s daughter, arrives with other young exiles including Bellamy, who is intent on protecting his sister Octavia. Their apparent freedom immediately proves fragile: Jasper is speared by an unseen inhabitant, and the group must reckon with an inhabited world rather than an empty refuge. The parallel story above them is about dwindling resources and adults weighing who can be saved. This opening establishes the basic conflict that continues through the series: survival depends on decisions made under pressure, yet each group’s idea of protecting its own people can put others at risk. The show expands from a landing-camp crisis into a conflict among communities formed by the catastrophe.

‘The 48’ picks up after the first season’s battle separates the survivors. Clarke wakes in a white room at Mount Weather, where President Dante Wallace offers her security and comfort but leaves her uncertain about the rest of her friends. Elsewhere, Bellamy and Finn are in danger, while Lincoln and Octavia try to escape toward the coast after Octavia is poisoned. The Ark’s survivors, now on the ground, face their own physical and moral problems as they search for the missing young people. The episode uses Clarke’s isolation to make Mount Weather’s apparent refuge feel suspect: she has food and shelter, but no reliable knowledge of who was rescued or what happened to the others. The scattered storylines bring former enemies and separated groups into a new geography, where survival requires finding one another as well as understanding the mountain’s intentions.

“Spacewalker” turns Finn’s massacre of a Grounder village into the price of peace. Lexa demands his death before granting a truce. Abby refuses to surrender him, and Clarke, Bellamy and Raven try to hide him, dividing their camp between loyalty to a friend and fear of another war. Finn eventually gives himself up. Lexa will let Clarke say goodbye but refuses mercy, so Clarke stabs Finn to spare him a prolonged execution. The act satisfies the demand for his life while devastating the people who loved him. Flashbacks to the Ark show his earlier relationship with Raven and the spacewalk he helped arrange for her. That tenderness cannot undo what he later did on Earth. The episode forces Clarke to carry both truths: Finn was someone she cared about, and his victims’ community was entitled to demand consequences.

Mount Weather makes Clarke’s next decision still harder. Its leaders take bone marrow from captured outsiders so their own population can survive outside the mountain. With Abby subjected to drilling, Clarke threatens to irradiate the occupied level unless Cage releases her people. Kane offers voluntary donations, but Cage rejects a compromise. Monty prepares the ventilation system, and Clarke and Bellamy pull the lever together. Their friends survive, while the mountain’s residents die, including children and people who helped the prisoners. Jasper loses Maya, who dies in his arms, and cannot accept their justification that there was no other way. The rescued group returns to Camp Jaha, but Clarke leaves rather than resume life among them. The victory has saved her community by destroying another, leaving grief and distrust inside the very group she meant to protect.

Later seasons widen the consequences. Conflict grows in Arkadia and Polis alongside Jaha’s effort to draw people into ALIE’s City of Light, and a looming nuclear disaster as reactors threaten to make Earth uninhabitable again. The groups race to secure shelter, including a bunker that can preserve only a limited population; leadership becomes a fight over who is admitted and who is left outside. After the survivors spend years in space, Monty’s message leads them toward Sanctum, where cryosleep offers a new start but the settlement’s apparent safety conceals the Primes’ control over its inhabitants. Clarke and Bellamy confront the cost of entering a society whose stability depends on other people’s bodies and memories. The changing settings—from bunker to orbit to Sanctum—keep repeating the question of whether survival can be organized without sacrificing someone else.

In the series finale, ‘The Last War,’ Clarke reaches the test that Cadogan believes will decide humanity’s future. She kills him during the process, so the Judge appears to her as Lexa and rules that Clarke herself cannot transcend. Raven appeals the judgment, asking the examiner to reconsider humanity. On Bardo, Octavia persuades the opposing armies to stop fighting rather than fulfil their expectation of a final war. Their decision gives the Judge evidence of change, and humanity is permitted to transcend. Clarke returns to Earth rather than joining the collective state. Madi remains transcended because she would have no peer her own age among the few humans who return, but Clarke is not left alone: Raven, Murphy, Emori, Octavia, Echo, Indra, Jordan, Miller, Jackson, Niylah and others choose mortal life with her. The Judge explains that they will not have children and will die permanently, yet the group reunites by the lake. The finale resolves the series’ repeated contest between abstract survival and personal bonds by making Clarke’s remaining friends choose shared finite lives.