The tropes, cliches, and patterns that underlay any story.
Every story, every book, every game follows them to some degree.
They are the reason the hero always wins.. or doesn't.
The reason why there's a happily ever after..
The reason the exposition fairy exists, or why the knight always rescues the damsel in distress.
Such are the laws of the story world.
“She'd become a governess. It was one of the few jobs a known lady could do. And she'd taken to it well. She'd sworn that if she did indeed ever find herself dancing on rooftops with chimney sweeps she'd beat herself to death with her own umbrella.”
― Hogfather