She Lost Her Spot. I Lost My Patience

I am in the middle of hosting an international conference when my younger sister, Aubrey Keller, suddenly calls me. She is sobbing over the phone as she says, "Aster, my spot in the student exchange program was taken away…" I immediately rush over to Aubrey's university campus. She's cornered in the teachers' office, her eyes brimming with tears. A young girl with punk flair is standing in front of Aubrey, gesturing at her with disdain. "Trying to fight for the spot against me, are you? I'm the heiress to the Keaton family in Centuria. "My father even funded an entire laboratory building for the university! Who do you think you are?" A teacher standing to the side is also adding fuel to the fire. "Aubrey, Ophelia's father is one of this university's key funders. Why don't you just let this go this time so we can all move on?" I'm about to rebuke the two when I hear the phrase 'heiress to the Keaton family.' Keaton family from Centuria? Since when did my father, Tristan Keaton, have another daughter besides Aubrey and me? I immediately call Tristan's number and ask coldly, "Dad, when did you cheat on Mom and sire another daughter behind her back?"