S5, E13: The acclaimed series that has explored the human condition through the prism of parallel universes, unexplainable phenomena and unimaginable threats, reaches a milestone 100th episode and its epic and climatic conclusion. After Olivia’s dangerous and otherworldly journey into the unknown, she, Peter, Walter, Astrid and Broyles face off against the Observers in one final and extraordinary battle for the fate of mankind. The five-season saga comes to an epic and emotional end in the exciting conclusion of a special two-hour series finale episode.