[Y/N] lived with her adoptive mother Toriel for a while. How long is that? About three years. Throughout the time, the monsters in the Ruins know her as if they were her siblings.
Flowey became way nicer each day around her, losing his soulless behavior. He cares about her so much he promise to protect her.
All was well...
Until she sneaked out of the Ruins. Going from Grillby's to the Librar(b)y, she went around having fun. Laws did apply, 16 being the age to leave past curfew, 18 being the age to finally date, and 21 to legally marry.
One day, I slipped from my own mouth of the presence of a Princess...
And Asgore ordered the Royal Guard to break the door to the Ruins...
(Cover art made by Zayn-Inverse on DeviantArt)