"I know what it is to be the spare. Your son didn’t deserve to be killed, Mr Diggory. We can help you get him back."
-- Albus Potter (CC1.14)
Amos Diggory is highly suspicious of the motives of both Albus Potter (as Harry Potter’s son and a Slytherin) and Scorpius Malfoy (the “son of Voldemort”). Delphi intervenes and convinces her uncle to listen to their plan to save his son Cedric by going back in time (CC1.14).
Occurs during the afternoon of 1 September 2020, after Scorpius and Albus jump off the train but before their parents find out they are missing that evening.
From the Web
Pottermore: Harry Potter and the Cursed Child
The theatre production opened in the West End of London at the Palace Theatre on 31 July 2016, with Esther Smith in the role of Delphi, Barry McCarthy as Amos Diggory, Anthony Boyle as Scorpius Malfoy and Sam Clemmett as Albus Potter: Harry Potter and the Cursed Child, Parts One and Two