Harry Potter and the Cursed Child Act II, Scene 16

Hogwarts, Library

• Scorpius finds Albus and insists they talk.
• It's an important plot dump, explaining that they changed history.
• When they sabotaged Cedric as Durmstrang boys, Hermione suspected Durmstrang was behind it.
• So she refused to go to the ball with Viktor Krum.
• That led to Ron never getting jealous, which meant they never fell in love.
• Albus thinks they need to go back in time—again—to fix things.
• Scorpius tells Albus to get over his daddy issues, because they're making him a terrible friend.
• Professor McGonagall, using the Marauder's Map, almost finds the boys, but they hide under Albus' invisibility cloak.
• After the scare of almost being found, Albus admits to Scorpius that he doesn't believe he's Voldemort's son because he doesn't think, "Voldemort is capable of having a kind son" (2.16.78).
• That's enough to make them friends again.
• With Albus and Scorpius' friendship re-cemented, they agree to find their way back to the Triwizard Tournament.