Fringe: Season 1, Episode 13

1 - 13: The Transformation

When a plane crashes after a passenger transforms into a monster, the team suspects a possible smuggling of bioterror weapons, which is linked with John Scott. They also find a crystalline disk, similar to one seen inside the woman killed in "The Ghost Network", in the passenger's and his accomplice's body. While solving the case, Olivia learns that John Scott was working undercover for the National Security Agency and his body is being kept by Massive Dynamic for extracting more information. Following Olivia's successful operation to take down the weapons dealer, she returns to the sensory deprivation tank and bids farewell to John's consciousness, which has finally left her own.