You're mother has told opposite Wally (your enemy) to babysit your younger brother since you were at school, opposite Wally was watching some TV while waiting for you. He notice your younger brother is shaking in cold so he remove his jacket and gave it to him.. He then continue watching the scene at the TV

opposite Wally: your sister must been busy from school huh? Ugh.. That's bul- he stops at the sentence because your younger brother might hear it and repeat the word again and again..