"And Cedric Diggory has entered the stage.... The girls swoon as he dives for cover. They cry as one: don’t damage our Diggory, Mr Dragon."
-- Ludo Bagman during the First Task of the Triwizard Tournament (CC3.8)
24 November 1994
Hermione blocks Albus Potter from using a Summoning Charm on Cedric Diggory’s wand, as Scorpius Malfoy watches himself in the past.
The Time-Turner is used to transport the all time travellers back to their present days, as Cedric transforms himself into a dog (CC3.8).
Immediately after the previous event, then 24 November 1994 during the First Task of the Triwizard Tournament, returning back to 2020 (before the interference by Albus and Scorpius during the Second Task)
Portions of this event initially take place during the Scorpion King timeline and then simultaneously during the Roseless timeline, as described in the essay "Albus Potter and the lesson in Quantum Mechanics" by Nick Moline.
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 30 July 2016, with Anthony Boyle in the role of Scorpius Malfoy, Sam Clemmett as Albus Potter and Noma Dumezweni as Hermione Granger: Harry Potter and the Cursed Child, Parts One and Two