LitCharts assigns a color and icon to each theme in Harry Potter and the Cursed Child, which you can use to track the themes throughout the work.
Parenthood
Time, Mistakes, and the Past
Friendship, Family, Love, and Bravery
Reputation and Expectation
Death and Sacrifice
Summary
Analysis
At a Muggle train station, Albus and Scorpius debate how to get information, knowing that they can’t talk to Muggles about Delphi. Albus is frustrated; he knows that Harry will think he ran away on purpose. Scorpius is exasperated by the fact that Albus is still thinking about their relationship when they’re permanently lost in time.
This exchange reveals how Albus and Harry still have a great deal of conflict in their relationship. Albus doesn’t feel fully understood, knowing that Harry will assume that he’s trying to prove himself or run away from his family again. However, Harry does know that they’ve been kidnapped and cares deeply about getting his son back, suggesting that their relationship is improving and that he actually does see Albus more clearly than Albus thinks.
Active
Themes
The Stationmaster approaches, telling Scorpius and Albus that the train is running late and handing them an amended timetable. Seeing the date on the timetable, Albus realizes Delphi’s plan. It’s October 30th, 1981—the day before Hollow’s Eve, the day that Voldemort attacked Harry as a baby. Albus realizes that she isn’t trying to bring about her prophecy—she’s trying to prevent the one in which Voldemort curses himself trying to kill the baby Harry Potter. Delphi is going to kill Harry herself, and they need to get to Godric’s Hollow to stop her.
As Scorpius and Albus realize the date, and Delphi’s plan as a result, it again shows how she has become fixated on the past. Rather than try to affect change in 1995, she has gone back even further to prevent Voldemort from becoming weakened in the first place by attacking baby Harry. The play illustrates how she is obsessed with trying to make the past—and thus the future—into what she wants it to be, and because she is positioned as the villain, the play now implies that it’s even sinister to try and change the past in this way.