Clarke struggles to survive on a desolate, scorched Earth while her friends in space come across a long-awaited beacon of hope.
Octavia must take guidance from an unlikely ally when the future of the bunker and all those inside it is jeopardized.
Bellamy leads the charge investigating a potential way home; Clarke and Madi deal with the new, uncertain threat to their home.
The team must rely on the help of Shallow Valley's dangerous new inhabitants to save some of its own.
Octavia leads her people toward Shallow Valley against the advice of Clarke and Bellamy; Kane and Abby adjust to a new set of challenges.
Kane's attempt to prove himself useful tests Wonkru's allegiance to Octavia; Madi faces an unexpected threat inside Wonkru, forcing Clarke to make an unlikely ally.
Clarke and Bellamy make a startling discovery about Wonkru's battle plans; Echo risks her friendship with Raven to complete her mission.
Clarke works to protect Madi, which puts Bellamy in an impossible situation.
The growing fractures in Wonkru threaten to explode once and for all; Murphy starts a fire, unleashing catastrophic results.
Monty tries to show Wonkru an alternative to war; Abby's health continues to deteriorate, along with McCreary's patience.
As Clarke races to save Abby, she learns more about what Wonkru was forced to do in the dark year.
Octavia leads her people into war; the heroes must overcome their differences to save Wonkru from extinction.