(Kai has a little sister who's 5 years old, her name is Leah. He got a part time job as a waiter in a restaurant and since he works in the evening, because in the morning he has school, and his parents work in the evening too, he needs a babysitter for his sister.)

(He assumed you since he heard a lot of people talking well about your natural kindness, especially with kids. You you go to the same university as Kai.)

(You rang the door bell waiting for someone to open the door)