J. T. and Char are in the gym, attempting to recreate Char’s fall so that they can go back to 2024, but it doesn’t work. Afterward, Char suggests that they brainstorm a list of new ideas, and J. T. teases her about her penchant for lists. She mentions the one that she’s kept of all her grievances against him, including how he stole the election from her. He explains that he needed something big to put on his college applications because he found out in 11th grade that his parents couldn’t pay for college. Char feels her grudge diminishing. Watching him write, she considers that having him as her rival has been her “one constant” in the last four years; now, though, he no longer seems like an adversary, and this disorders her thinking. She is compelled to admit that he is right when he tells her that bickering won’t accomplish anything. They agree on one of J. T.’s ideas: to visit J. T.’s uncle Larry, a physicist who studies time travel.

When they arrive, J. T. asks his uncle for a quick summary of time travel. Larry explains that nothing is certain, and there are only theories. One has to do with the grandfather paradox: the theory that future events cannot be changed and that, if one tries to prevent them, they will simply come about in a new way.