Liberty (Fringe)
"Liberty" is the twelfth episode of the fifth season of the Fox science-fiction/drama television series Fringe, and the show's 99th and penultimate episode. It aired on January 18, 2013, with the series finale, "An Enemy of Fate", in the United States on Fox and in the UK and Ireland on Sky1.
Plot
After Michael gives himself up to Captain Windmark, he is taken to a security facility on Liberty Island, where he attempts to study Michael. Windmark finds the boy's mind impossible to read and orders more invasive diagnostics to determine what Michael is. Discovering that the boy's intelligence exceeds that of the Observers while his emotional capacity exceeds that of standard humans, Windmark returns to 2609 to suggest to his superior that they destroy the child to protect themselves, but instead is told to simply "disassemble" the boy for future study.Broyles learns of Michael's location and relays it to the Fringe team, but cautions them that the facility is nearly impossible to infiltrate. While brainstorming, Olivia suggests that she be re-injected with Cortexiphan to let her cross over to the parallel universe, travel to Liberty Island there, cross back and retrieve Michael, and then repeat these steps to get back safely. However, Peter worries about the effects of re-dosing Olivia with potentially lethal levels of the drug, while Walter is concerned with the unknown condition of the parallel universe. Astrid suggests using the window to determine the state of the parallel universe, and through this, they find that there are no signs of the Observer invasion there, giving Olivia's plan credibility.
While September returns to the lab to start assembly of the device to send Michael into the future, the Fringe team goes to an underground safehouse to prepare Olivia for crossing over. Walter administers four doses—one for each expected crossing—despite the harm it does to her. As the drug takes effect, Peter and Walter have a discussion about the nature of sacrifice. When Olivia recovers from the injections, Walter warns her of how long she has and that jumping too fast will cause rapid withdrawal symptoms.
Olivia jumps near the site of the parallel-universe Fringe Division building, where she is met by her doppelganger and current leader of Fringe Division, Fauxlivia, and her former partner from the prime universe, Lincoln Lee; the two have since married and have a son. They arrange transport to Liberty Island and take her to the coordinates they believe Michael is being kept at; Olivia crosses over but finds too late that the boy is being taken to surgery, while she herself starts experiencing double visions of the two universes. She fights her way through Observers, and stops the operation in time, with Michael smiling at the sight of her. With the boy, Olivia crosses back over, where Fauxlivia and Lincoln help to stop an Observer who followed her back across. Olivia thanks them for their help and crosses back over at Battery Park with Michael.
In the conclusion, Windmark discovers that Broyles has relayed Michael's location to the Fringe team. Meanwhile, September has completed the device, but one component fails to work. He goes to December, and requests a favor.