100 years in the future, when the Earth has been abandoned due to radioactivity, the last surviving humans live on an ark orbiting the planet — but the ark won't last forever. So the repressive regime picks 100 expendable juvenile delinquents to send down to Earth to see if the planet is still habitable.
Clarke and her friends attempt to rebuild Sanctum as a new threat rises in the woods.
Echo and Gabriel learn more about Hope and her mysterious past.
Raven faces an unexpected threat. Clarke must keep the peace among opposing factions in Sanctum.
Mysterious outsiders arrive with news of Clarke's missing people.
Octavia gets to know a whole new world. Meanwhile, Murphy and Emori play make believe.
Clarke and her friends find themselves on a planet that is not what it seems.
Emori tries to heal Sanctum's old familial wounds while Echo, Octavia and Diyoza struggle with new ones.
Clarke confronts a new adversary. A surprising connection takes us back to the past and to the nuclear apocalypse that destroyed the Earth.
Murphy and Indra must defuse a tense situation. Old friends make new allegiances.
Sheidheda makes his move. A Disciple goes rogue.
Where in the universe is Bellamy Blake?
It's a new day in Sanctum. Clarke, Octavia, Raven and Echo struggle with a new foe.