Season synopsis
Contains spoilers for this season and earlier seasons.
The fourth season follows the survivors as the coming Praimfaya, the chain of reactor meltdowns ALIE warned about, turns every shelter into a deadline. Clarke, Abby and their allies test Nightblood as a possible way to survive the radiation, while a feud over the few safe spaces puts Skaikru at odds with the Grounder clans. Jaha finds the Second Dawn bunker, and the survivors must decide who can enter it; Octavia fights in the conclave to determine the bunker’s fate. Octavia declares the clans one people, Wonkru, and agrees to lead the residents below.
As Praimfaya reaches Polis, Octavia tells the bunker residents they must survive together. At Becca’s lab, Raven’s plan to return to the Ark requires someone to align a radio dish at the tower; Clarke climbs it, knowing she will miss the rocket’s launch. Bellamy and Raven reach the Ring with the others, and Bellamy connects an oxygen generator just before the crew suffocates. The finale jumps six years and seven days: Clarke has survived on the ground because of her Nightblood and lives with Madi, a young Nightblood, while waiting for contact. Clarke cannot reach the bunker residents or her friends in orbit. When an Eligius prisoner transport descends, she tells Madi to hide their supplies and prepares to meet strangers.