[Warning: This story contains major spoilers from the series finale of Fringe. Read at your own risk!]
Ever since the moment Peter was erased, Fringe fans had hoped the Fox series would eventually get back to the original timeline with the original Fringe Division we had come to know and love. With the remaining team in 2036 attempting to reset time in order to get rid of The Observers, the series finale proved that traveling back that far was not necessary; Giving Peter and Olivia their happily ever after with their daughter was. Let's go back to how they got there:
Back in 2036, Michael, the anomaly, is in the clutches of The Observers, but Broyles discovers that he's being held in the Statue of Liberty. After being injected with Cortexiphan, Olivia crosses over to the other universe and uses the help of Bolivia and Lincoln — who have a family, while Walternate has retired from the DOD and still lectures at Harvard from time to time — to cross back and rescue Michael. Though Olivia is successful, Broyles' true allegiance to the resistance is uncovered, so he decides to lead the loyalists on a wild goose chase to buy the team more time.
Meanwhile, back at the lab, Peter finds a video tape from the past addressed to him in which Walter explains that Peter will have received a letter from him after he's disappeared. Walter admits he was planning to time travel to ensure the future of humanity, and he's going to accompany Michael into the future to complete the plan. But making a future without The Observers will create a paradox in which Walter and Michael would suddenly disappear in 2015; therefore, they need to live out the rest of their lives in the future.
However, because December — whom September turned to for help with the time traveling device — was being monitored, the remaining piece of the device that the team needs to trigger it ends up in the hands of Windmark, who is also able to capture Broyles.. That's why the team has to vacate the lab, but not before saying one final goodbye to Gene, the cow, whom Astrid found in amber. And not before Walter finally gets Astrid's name right. Tear.
Even though Walter believes his penance for all the devastation he's caused over the years was to accompany Michael into the future, September has seen his passion as a father and wants to be that man for his own son, so he decides to take Walter's place.
After Peter and Olivia secure the cube that calibrates the shipping lanes — and save Broyles in an awesome scene that recalls many of the old Fringe Division cases — the Fringe team and the loyalists battle the Observers to secure the shipping lane, which they will now use to time travel. However, Windmark shows up and tries to steal Michael, but Olivia distracts him by using the remaining Cortexiphan in her system and smashes him with a car. But when September and Michael race to the portal, September is killed and Walter must take his place.
The series then flashes back to the day in the park when The Observers originally invaded, but this time, they don't show up. Peter, Olivia and Etta are able to go home as a family, where Peter discovers that letter from Walter, which contains a White Tulip. Walter is gone, but Peter and Olivia get their happily ever after.
What did you think of the Fringe finale? Are you sad that Walter doesn't get to see Etta grow up? Are you glad that Peter and Olivia got their happy ending? Hit the comments!