I bet it would be about Harry Potter’s kids:

Harry Potter author J.K. Rowling has strongly hinted for the first time that she could write an eighth book in the series.
Rowling, 42, admits she has ‘weak moments’ when she feels she will pen another novel about the boy wizard.
One of her biggest fans ” her 14-year-old daughter Jessica ” has already put pressure on her to revisit the character.
[…]
“If – and it’s a big if – I ever write an eighth book, I doubt that Harry would be the central character. I feel I’ve already told his story.
“But these are big ifs. Let’s give it ten years.”
In the meantime, Rowling is working on two writing projects ” an adult novel and a “political fairy tale” ” and is involved in charity work.

(via)