For deeper analysis, you can check out reviews on Rotten Tomatoes or the IMDb Episode Guide for fan discussions on the finale's impact.

Despite the looming "Praimfaya" (nuclear apocalypse), Clarke pulls the lever, freeing everyone from Alie’s control but leaving humanity with a new, ticking clock for survival. Where to Watch & Key Info Information Air Date May 19, 2016 Director Dean White Main Cast

Eliza Taylor (Clarke), Bob Morley (Bellamy), Alycia Debnam-Carey (Lexa) Available on Max and Netflix

The 100 Season 3 Finale Review: Perverse Instantiation Part 2

To enter safely, Clarke uses the Flame (the AI of the Commanders) and receives an unexpected assist from the projection of Lexa , who helps her fight through Alie’s "minions."

Clarke eventually meets the spirit of Becca Pramheda (the first Commander), who reveals the kill switch. However, Alie counters by showing Clarke the truth: Earth's nuclear power plants are melting down, and the world will be uninhabitable within six months.

The finale follows Clarke as she enters the City of Light to find the "Kill Switch" for Alie, the rogue AI that has enslaved humanity's minds.