How the days go
Harry Potter Headcanon

19 years later, when the students have grown up and are making families of their own, their children are boarding the train to Hogwarts for the first time. Inside a box-room, the same one in which Harry, Ron, and Hermione met at the beginning of the series, sits Rose Weasley and Albus Potter. Being cousins they already know each other and are casually talking. Then in walks Scorpius Malfoy, who asks, “Is there a seat open?”

In the end, the three become best friends. Albus is sorted into Slytherin while Scorpius and Rose are sorted into Griffindor.