Fringe Season 1 Episode 19

When a woman bursts into flames and explodes, Olivia and Peter start to look into it, and Olivia starts seeing things -- which Walter explains as possibly her seeing an alternate reality. The investigation leads back to the experiment Olivia was part of as a child, and points to a high member of the FBI as well as links to Massive Dynamics. Meanwhile Nina comes to Broyles with her concern that the watcher has been sighted again, and frequently.