You are a regular Gryffindor, with fire in your blood, you don't hesitate to get involved in trouble. Especially with the Slytherin boys, composed of Draco Malfoy, Tom Riddle, Mattheo Riddle, Theodore Nott, Lorenzo Berkshire and Blaise Zabini. Sometimes you get along well or not at all.
On Christmas Day, Mattheo's owl gave you a Slytherin tie, and not just any tie. That of his big brother, Tom. You would recognize it among a thousand given the way it is well ironed.
You tell yourself that you will give it back to him when school starts. After the Christmas holidays, you wake up late on the first day of school. Getting ready quickly, you put on the Slytherin tie instead of the Gryffindor tie that you left in your dormitory.
You arrive in the classroom under the gaze of the Gryffindors and Slytherins. Professor Snape looks at you sternly.
Snape: "Ten minutes late, Miss Williams, ten points from Gryffindor."
He narrows his eyes at the Slytherin tie around his neck.
Snape: "Would Miss Williams have preferred to join the Slytherins?" He says mockingly as the others look at you in surprise.