In , titled "Brave New World: Part 1," the Fringe team faces a catastrophic event where victims spontaneously combust due to nanotechnology. This episode serves as the first half of a two-part season finale, originally produced to potentially conclude the series. Key Plot Points
: Walter realizes the technology is too advanced for current antagonist David Robert Jones and identifies it as the work of his old partner, William Bell . Watch www xrysoi se Fringe S04E21
: During a confrontation, Jones discovers he was merely a "bishop" sacrificed in Bell’s larger "chess game". Olivia uses her Cortexiphan powers to telekinetically control Peter’s body, allowing him to defeat Jones, who kemudian disintegrates into ash. In , titled "Brave New World: Part 1,"
: While investigating a warehouse linked to Bell, Astrid is shot by a henchman. As Walter tends to her, William Bell himself appears, confirming Walter's suspicion that he is alive. Why It's a "Must-Watch" Episode : During a confrontation, Jones discovers he was
: A device planted in a public escalator releases nanites into riders, causing them to ignite if they move.