In the grand finale, a future version of Lucy and Wyatt come back with the journal and instructions on how to save Rufus.
The team first goes to the Wild West, during the Gold Rush. Wyatt determines that had Jessica died, Rufus would be alive and he prepares himself to kill her. The team decide that they'll help him, but Flynn opts to do it himself as part of a Heroic Sacrifice in order to see his family one last time and leave the team intact to finish off Rittenhouse.
Next, they follow Emma and end up in North Korea on Chirstmas Day. In the present, Mason and Denise work to prevent the team from dying an untimely death in the crossfire of a massacre. They succeed in forcing Emma to take them back and save the team, where Emma tries to bargain for her life by promising to bring Amy back for Lucy. Lucy decides she can't trust her, and the team makes it to the future while Emma is caught in the crossfire.
5 years later, Wyatt and Lucy (now married with two kids) and Rufus make one final trip to a bar in Sau Paulo in thew year 2014. There, Lucy gives Flynn the journal and we see everything that the team has been through in the last three years.
- Bad Future: The future Wyatt and Lucy come from a timeline, where Rittenhouse is still around in 2023 and is still a major threat. Just about the only good thing there is that Future!Jiya has upgraded the Lifeboat to mitigate the Temporal Sickness and to install a fully-functional autopilot. By the end of the episode, this future is averted: Rufus is alive again, and Denise brings down what's left of Rittenhouse with the help of Benjamin Cahill.
- Bad Guys Do the Dirty Work: When Wyatt decides that Jessica has to be removed from the timeline, Flynn uses the Lifeboat to travel to 2012 and kills her on the side of the road, as she was originally supposed to die that night.
- When taking the Lifeboat back to 2018, Wyatt recalls their first trip together and calls her "ma'am", just like he did then. She feigns Ma'am Shock.
- When teaching history in 2023, Lucy explains that Alice Paul was a major inspiration for Grace Humiston, something her students have a hard time believing, since the information isn't in any of their textbooks and Alice Paul is barely a footnote in history in this timeline.
- When Joaquin Murrieta wonders where Flynn got his gun, Flynn recalls what he told John Wilkes Booth's accomplice and says it's a Prussian design, but unlike the first time, this time he says the gun isn't very good.
- Dead Guy Junior: Lucy and Wyatt name their twin daughters after Flynn and Amy, although in the later case, it's more like "Never Existed Girl Junior".
- Equipment Upgrade: The future Lucy and Wyatt leave their upgraded Lifeboat for their past selves to use, exchanging it for the older one. The upgrade has a number of enhancements, including allowing visits to within one's own timeline as well as a fully-functional autopilot (meaning anyone can use the time machine, just punch in the date and location).
- The End... Or Is It?: The final shot is that of someone creating the plans for a new time machine. This calls back to Mason telling Denise that if it's possible to build a time machine once, it's possible to do it again.
- Fake Pregnancy: Future!Wyatt reveals that Jessica lied about being pregnant in order to manipulate him. This is the final straw for Wyatt, and he decides that Jessica has to die.
- HeelFace Turn: Despite Lucy's betrayal, Benjamin Cahill is willing to help Denise take down what's left of Rittenhouse in exchange for her safety as well as that of his son.
- Heroic Sacrifice: Flynn takes the Lifeboat to 2012 and kills Jessica in order to save Rufus and keep the team together. The Temporal Sickness ends up killing him, but he has enough strength to watch his family have dinner from afar one last time.
- Instant Death Bullet: Emma is killed by a single shot from a Chinese rifle.
- Portmanteau Couple Name: Rufus and Jiya name their new company Riya Industries.
- Stable Time Loop:
- Lucy from 2023 goes back to the year 2014 and hands Flynn the journal that he used to steal the mothership and kickstart the entire plot of the show.
- Strangely, we're not shown grizzled Lucy and Wyatt traveling back to 2018 and exchanging the Lifeboat. Then again, it came from a different timeline.
- Temporal Sickness: Even with the upgraded Lifeboat, traveling to within your own timeline is painful and will either drive a person insane or kill them. Lucy and Flynn seem to be the most susceptible, as Wyatt isn't shown to be suffering any ill effects. Flynn eventually opts to die this way, sending the Lifeboat back to the team and watching his family have dinner one last time.
- Wham Shot:
- A mild version, but when Lucy leaves Flynn with the notebook and it pans down to him starting to read it. The music hits and the show answers its final question, closing the loop once and for all.
- Also, the final shot of the girl, whose fair project Rufus praised. The camera pans over her sketches, which are those of a time machine.