This could completely become a fictional story. During one of James's summer vacations, if he didn't have a whim to tease the sister who hurt Lily, then the subsequent story would not have happened at all.
We still have to emphasize that this is a fictional story, a story similar to Branches that may happen in a quasi-parallel world.
Petunia James Black Parent Generation
Intention: Confidence, self-improvement and self-reliance