The Past
The past is a central theme of the plot since so much hinges on what the characters remember and what they get the opportunity to change. Harry spends much of the play ruminating over his own childhood whilst considering how to best parent his child. Thus, the past becomes a method of gaining insight into character. The plot revolves around Albus and Scorpius's adventures with the Time-Turner; we follow the changes they make and watch them also undo these changes. However, the boys learn that the past should never be changed, even if it’s for ethical reasons, which is why Albus couldn’t save Craig Bowker Jr. even though he too was a spare just like Cedric Diggory. Albus and Scorpius realize that Cedric's death is an important part of history that they cannot change, and they are forced to let him die in his own account. Albus does, however, tell Cedric that his father loves him, showing his new appreciation for the rules the past: they cannot change the past, but they can ensure that they can help others feel loved as they accept their fate.
Father and Son Relationship
One of the similarities between Albus and Scorpius is their messy relationships with their fathers. When Albus goes off to Hogwarts and is sorted into Slytherin, he begins to feel that he is not living up to the names given to him by his father. Their relationship turns cold, leading to fighting and ending with Harry confessing that sometimes he wishes he wasn’t his son. In the end, they both agree that they are complicated people who need specific love and attention from the other to see each other fully. Draco and Scorpius's relationship is slightly different; Scorpius admires and loves his father. He knows that his father is raising him in a loving environment that he didn’t have when he was growing up. They are brought closer together through the death of Scorpius's mother, Astoria.
Ultimately, though the Potters' relationship is dysfunctional, Albus trusts in Harry. Albus sends a message to Harry in the future, letting him know where in history to come help him, without knowing that another Time-Turner exists. He sends the message believing that his father will find a way to save him. As the play comes to a close, Albus and Harry pledge to work harder at their relationship and each moves a small step toward understanding the other.
Role as a Parent
For Harry and Draco, it’s difficult being a parent; in Harry’s case he didn’t have a father, and Draco’s father Lucius was a difficult man. Both Harry and Draco are raising their own children in the way they think is best, but they are both trying to give them what they wish they had at that age, rather than raising them based on their needs. Over the course of the adventure, they come to realize that they need to spend time with their children so they can give them the specific love that they need. Draco is a single father, heartbroken over his wife's death, making it difficult for him to communicate with Scorpius on a meaningful level. When Draco and Harry arrive at Godric's Hollow with the other adults, Ginny and Harry rush to hug Albus. Draco tells Scorpius they can hug if Scorpius wants, and they enter into an awkward embrace that does not last long, demonstrating the differences in approach regarding physical touch in the two families. The fathers learn from each other as do the sons, as they find new ways to connect as fathers and sons.
Rumors
Rumors play a large part in the story. The rumors of the existence of a Time-Turner leads to Delphi's plot involving Amos Diggory trying to spare his son's life. The entire plot of the story is based on the substantiveness of this rumor. However, some rumors are less substantive; the rumor that Scorpius is the son of Voldemort is baseless and affects Scorpius's social life negatively. Overheard conversations and rumors ultimately lead to characters taking action while not fully grasping their situation; Albus and Scorpius take action with Amos Diggory by confirming the rumors of the Time-Turner, ironically wanting to change the past because of the misery caused to Scorpius by the Voldemort parentage rumor.
Living Up to a Legacy
Albus suffers at the beginning of the play because he has to live up to his father’s legacy. Harry Potter was a famous wizard who destroyed the most powerful dark sorcerer in the world at seventeen, and Albus feels he has nothing to show for himself. He is neither a star student nor a successful Quidditch player. Named after two famous wizards, Albus Dumbledore and Severus Snape, Albus Severus's first and middle names often feel like more of a challenge to meet rather than an honor to their memory. Harry later tells Albus that he should never have to feel as if he had to maintain the same level of greatness of these two wizards—Snape and Dumbledore were two great wizards who also had their own trail of mistakes.
Friendships
The friendships in the play are both a subject of joy and sorrow. Harry Potter's role in the trio brings him comfort, but it also draws jealousy from Draco Malfoy and, ironically, his own wife. The bonds of friendship also cast an expectation on Harry's children to have a group of friends, and although Albus has a deep bond with Scorpius, they often feel as if they are outcasts together rather than popular. Ultimately it is the strength of these friendships that leads to the defeat of dark forces, mirroring the ultimate message of the Harry Potter series.
Concealment and Deception
Many characters in the play conceal their identity or their true motivations. Scorpius, Albus, and Delphi use polyjuice potion to masquerade as Harry, Ron, and Hermione respectively in order to gain access to the Ministry of Magic to steal the Time-Turner. However, Delphi also conceals her true identity as the daughter of Voldemort and pretends to be a part of the Diggory clan to manipulate the boys into assisting her quest to bring back Voldemort's reign. Though deception is used mainly by the antagonist, the parents also deceive their children with their reasonings behind the decisions they make in trying to keep the boys away from each other.
