About everything that happened in the seven years of Hogwarts——
Mainly about the two houses Slytherin and Gryffindor
There are also the Black family, the Malfoy family, the Potter family, the Weasley family, etc.
(Of course there are also private ones)
The timeline roughly runs through the ending of "Deathly Hallows", which is the scene where the trio have families and send their children to Hogwarts. And some plots from "The Cursed Child"
Intention: growth