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
Harry wakes from his nightmare—he fell asleep sitting on the staircase. Ginny enters, saying that they haven’t had any news about Albus. Harry explains that he was dreaming about his childhood, then he heard Voldemort and saw Albus wearing Durmstrang robes. Harry realizes that he might know where his son is.
Harry’s explanation of the dream to Ginny shows the beginning of Harry conflating the two issues of Voldemort returning and his struggles with Albus, which will ultimately prove quite harmful to Albus, as Harry’s dream suggested. In this way, the play suggests the dangers of worrying about the past when trying to resolve issues in the present.