- Season 4 — The 100

Much of the season involves the search for a viable "Lifeboat." This includes the repair of Arkadia, the discovery of a hidden Second Dawn bunker, and the high-risk experiments with "Nightblood" to create radiation immunity.

The artificial intelligence ALIE may be gone, but her warning was true. The remaining nuclear power plants are melting down, and a wave of radiation is set to wipe out all life on Earth in six months. The season focuses on the desperate race to find a way for the human race to survive. Key Storylines The 100 - Season 4

A brutal, Hunger Games-style battle royale determines which clan gets to inhabit the bunker. Themes to Watch Much of the season involves the search for

Keep an eye on characters like Octavia , who transitions into a fierce leader, and Raven , who faces immense physical and mental hurdles. Helpful Tip The season focuses on the desperate race to

The series continues to ask, "How far are you willing to go to save your people?"

Roan (Ice Nation) and Octavia (Skaikru) struggle to maintain a fragile peace between the 13 clans as resources dwindle and the end of the world approaches.

Pay close attention to the lore introduced early on; it becomes the most critical plot point for the season's high-octane finale and the setup for Season 5.