: Bell intends to use Olivia Dunham as a biological power source. Her high levels of Cortexiphan make her a "living battery" capable of fueling the destruction of existing realities to create a "Brave New World" under his control.
While the immediate threat of Bell is neutralized, the finale's epilogue shifts the tone. September the Observer appears to Walter, warning that directly setting up the Observer invasion and the dystopian future of the fifth and final season. Fringe: Season 4 Episode 22 - Brave New World Part 2 Fringe - Season 4Eps22
: To stop the collapse, Walter Bishop makes the unthinkable choice to shoot Olivia in the head . Because the Cortexiphan is actively regenerating her brain tissue, the bullet's impact disrupts the energy flow, saving both universes but forcing Bell to flee. Key Reveals & Character Arcs : Bell intends to use Olivia Dunham as
: The episode features creepy practical effects, notably Jessica Holt's face contortion, which was performed without CGI by actress Rebecca Mader . September the Observer appears to Walter, warning that
The episode centers on William Bell’s megalomaniacal plan to collapse both the "Blue" and "Red" universes.
: After Walter extracts the bullet and Olivia miraculously heals, the team is told that the Fringe division will be funded once more.